The suspect, 45, was seen starting the fire in the five-story building at 41 Spring Street, near Mulberry Street, in the heart of NoLIta, around 6:40 p.m., the police said.

The man, whose name was not released by the authorities, fought with first responders, trying to stop them as they tried to battle the blaze, the police said. He was arrested and taken to New York Downtown Hospital with bruises. The mother and child were taken to a police station "in good health," said Paul J. Browne, the chief spokesman for the police.

The dead person was found on a third-floor fire escape, but the authorities said they did not know if the person lived in the building or even whether it was a man or a woman. The body was "burned beyond recognition," Mr. Browne said.

It took nearly 200 firefighters two and a half hours to bring the fire under control, fire officials said; the building has a Pinkberry shop on the ground floor and apartments above.

"We had an extraordinary amount of fire," said James Esposito, chief of operations for the Fire Department. It burned upward to the roof, destroying the interior staircases, so firefighters had to use fire escapes and ladders. "It was an extremely intense operation," Chief Esposito said. "The fire encompassed all the walls, all the floors," he said. "We have a partial collapse inside the building right now. It's essentially destroyed."

Seven firefighters and at least two other people were injured. A police officer broke his hand in the fight with the suspect.

William Bray, 25, a chef who lives a block away, said he ran into the street when he saw flashing lights coming from the building. "There were flames coming out of the second-floor window," he said. "Then, soon after, we began to see smoke billowing out of the third-floor windows."

He said he saw the suspect being led from the building in handcuffs. He was not wearing shoes, had blood on his shirt and a black eye, Mr. Bray said. He said he recognized him as someone who frequented the park opposite the building with a young son.

Optimistic predictions by RAND in 2005 helped drive explosive growth in the electronic records industry and encouraged the federal government to give billions of dollars in financial incentives to hospitals and doctors that put the systems in place.

"We've not achieved the productivity and quality benefits that are unquestionably there for the taking," said Dr. Arthur L. Kellermann, one of the authors of a reassessment by RAND that was published in this month's edition of Health Affairs, an academic journal.

RAND's 2005 report was paid for by a group of companies, including General Electric and Cerner Corporation, that have profited by developing and selling electronic records systems to hospitals and physician practices. Cerner's revenue has nearly tripled since the report was released, to a projected $3 billion in 2013, from $1 billion in 2005.

The report predicted that widespread use of electronic records could save the United States health care system at least $81 billion a year, a figure RAND now says was overstated. The study was widely praised within the technology industry and helped persuade Congress and the Obama administration to authorize billions of dollars in federal stimulus money in 2009 to help hospitals and doctors pay for the installation of electronic records systems.

"RAND got a lot of attention and a lot of buzz with the original analysis," said Dr. Kellermann, who was not involved in the 2005 study. "The industry quickly embraced it."

But evidence of significant savings is scant, and there is increasing concern that electronic records have actually added to costs by making it easier to bill more for some services.

Health care spending has risen $800 billion since the first report was issued, according to federal figures. The reasons are many, from the aging of the baby boomer population, to the cost of medical advances, to higher usage of medical services over all.

Officials at RAND said their new analysis did not try to put a dollar figure on how much electronic record-keeping had helped or hurt efforts to reduce costs. But the firm's acknowledgment that its earlier analysis was overly optimistic adds to a chorus of concern about the cost of the new systems and the haste with which they have been adopted.

The recent analysis was sharply critical of the commercial systems now in place, many of which are hard to use and do not allow doctors and patients to share medical information across systems. "We could be getting much more if we could take the time to do a little more planning and to set more standards," said Marc Probst, chief information officer for Intermountain Healthcare, a large health system in Salt Lake City that developed its own electronic records system and is cited by RAND as an example of how the technology can help improve care and reduce costs.

The RAND researchers pointed to a number of other reasons the expected savings had not materialized. The rate of adoption has been slow, they said, and electronic records do not address the fact that doctors and hospitals reap the benefits of high volumes of care.

Many experts say the available systems seem to be aimed more at increasing billing by providers than at improving care or saving money. Federal regulators are investigating whether electronic records make it easier for hospitals and doctors to bill for services they did not provide and whether Medicare and other federal agencies are adequately monitoring the use of electronic records.

Technology "is only a tool," said Dr. David Blumenthal, who helped oversee the federal push for the adoption of electronic records under President Obama and is now president of the Commonwealth Fund, a nonprofit health group. "Like any tool, it can be used well or poorly." While there is strong evidence that electronic records can contribute to better care and more efficiency, Dr. Blumenthal said, the systems in place do not always work in ways that help achieve those benefits.

Federal officials say they are drafting new rules to address many of the concerns about the current systems.

Looking forward, Mr. Geithner has no plans. A regulator of Wall Street but not a creature of it, he will probably be the least likely former Treasury secretary to land there. "I'm going to take a long time," he said in the second of two exit interviews, one conducted in the midst of the recent fiscal fight and one just after the news conference on Thursday at which President Obama formally nominated his successor, Jacob J. Lew.

Looking back, he is remarkably sanguine. He is comfortable with his decisions: the policy choices available to him were far from ideal, he said, but his team did the best it could within the realm of the politically possible. "It was a very bad crisis. No playbook. No road map. No clear precedent," he said. "If we had a different set of constraints, particularly in fiscal policy, then I think that the economic outcome could have been modestly better."

A sense of the weight of those constraints emerged in the brief speech Mr. Geithner gave at the White House news conference on Thursday, as Mr. Obama thanked him for his service. While describing the "compelling and rewarding work" of government, he mentioned the "divisive state of our political system."

In the interviews, Mr. Geithner, 51, returned to the idea that the Treasury and the Obama administration might have done more if they had been given more latitude by Congress.

"The way our country is structured, by design, the founders left the Congress with all the meaningful authorities to determine the path of the economy and what you could do in a crisis," he said, mentioning how hard the White House had pushed for more authority. "The scale of the fiscal response in particular was dependent" on what Congress would allow.

Mr. Geithner ran the Treasury during the tumultuous years of the financial crisis and a recession that slowly gave way to a recovery, albeit an unsteady one. As president of the Federal Reserve Bank of New York before he joined Mr. Obama's cabinet in 2009, he was at the center of the most nerve-racking moments of the banking crisis. And his low-key but forceful insistence kept the Treasury at the center of every major economic policy decision of Mr. Obama's first term, aside from the health care overhaul.

By a combination of historical accident and his own design, Mr. Geithner will go down as one of the most influential Treasury secretaries, alongside figures like Robert E. Rubin, who served under President Bill Clinton, and Henry Morgenthau Jr., who served under Roosevelt.

But he has not always been a popular one. Both Republicans and Democrats have accused him of subverting capitalism and dedicating taxpayer money to "too big to fail" institutions in perpetuity. The left has criticized him for helping "fat cat" bankers instead of regular people, especially underwater homeowners.

"Is the system safer today?" said Dennis M. Kelleher, president of Better Markets, a nonprofit that advocates stricter financial regulations. "The collapse turned an implicit public guarantee into an explicit public guarantee. It is one of the most dramatic changes of federal policy in history and puts too much at stake."

Still, Mr. Geithner has attained something like a first-among-equals stature at the White House. He is one of the only top-level staff members to have remained throughout Mr. Obama's first term, and his word and policy judgments have prevailed in fight after fight and negotiation after negotiation.

"He went from someone who people were unsure of in the first six months to achieving the elevated status of being the guy who made the toughest and loneliest calls at the most politically perilous moments — and turned out to be right," said Gene B. Sperling, director of the National Economic Council.

In many ways, his colleagues said, Mr. Geithner's job seemed at times to be that of a firefighter or, at its worst moments, a glorified janitor. His four years were filled with a series of crises: the collapse of the financial system, spiraling unemployment, the cratering housing market, the financial reform bill, the ailing auto industry, the European debt crisis, a debt ceiling standoff and two protracted budget negotiations.

"He is so serene in good times and in bad," said Michael Froman, a deputy national security adviser who has known Mr. Geithner for two decades and helped introduce him to Mr. Obama. Given Mr. Geithner's background fighting financial disasters abroad as a Treasury aide, Mr. Froman said, "I think he was better prepared than anyone to deal with these crises."

The decisions Mr. Geithner made during the financial crisis remain among his most controversial. For instance, he quashed proposals to seize bonuses, impose new taxes or otherwise punish bankers, whose pay rebounded quickly after the collapse.

Mr. Geithner refers to such proposals as the "Old Testament" part of the rescue and reform effort. "We just didn't see a more effective response," he said. "If you're governing, your responsibility is to do what you think is going to be best for the welfare of the country." More punitive measures might have been emotionally satisfying, administration aides said, but they might also have put taxpayer dollars at risk by destabilizing the banks.

Housing is another area in which Mr. Geithner's leadership has been criticized. The Obama administration estimated at first that it could reach three million to four million homeowners with its mortgage plans, but it has aided less than half that number and left billions of dollars unspent.

"Our authority on housing was very, very limited," Mr. Geithner said. "We were able to use a significant amount of the authority in the Troubled Asset Relief Program to design a program for modifying the loans of a pretty substantial fraction of Americans facing foreclosure. But we had no legal authority to compel banks to provide mortgage relief. All we could do was find incentives."

He added, "It's not clear with greater authority we would have been able to achieve a significantly faster pace of improvement."

Such technocratic responses are typical of Mr. Geithner. His aides say that empathizing with the public and communicating his anger or disappointment with the slow pace of the recovery have always been among his weak points.

He has struggled at times with the outward-facing role of the Treasury secretary. He dislikes speaking with the press and bristles at being a "potted plant" trotted out at news conferences, for instance. Aides said they prepared him for media appearances as if playing the game Taboo, banning him from using phrases like "credit-default spreads."

But within the White House, Mr. Geithner's technocratic skills and no-drama attitude, as well as his calls on how to deal with the crisis, made him one of Mr. Obama's most trusted aides. Though he is mostly known for his work on the financial crisis, he was also the White House's main emissary to Europe on its debt crisis and spent hundreds of hours working on fiscal negotiations with Congress. During his tenure, he made 61 domestic trips and 37 international ones, and testified 67 times to Congressional committees.

Looking back, he said, more authority or financing from Congress might have helped the administration promote the recovery. But he said he felt comfortable otherwise.

Asked directly how he viewed his tenure, however, Mr. Geithner shied away. "I kind of think that's better for history to answer," he said.

But an aging and shrinking order of Cistercian monks have accomplished what great men and cities could not: the reconstruction of Santa Maria de Óvila's most architecturally significant building, a 12th-century Gothic chapter house. The monks ascribed the successful restoration to their faith, though years of tenacious fund-raising, as well as a recent alliance with a local beer brewer, also helped.

"The meaning that this holds for us, and the link to hope, is that it may take generations," the Rev. Paul Mark Schwan, the abbot of the New Clairvaux monastery, said of the restoration. "What appears dead, or almost dead, rises again."

With the major work complete, the chapter house was opened to the public last year.

"We got into possession of the stones, and they've come home — a long ways from Spain, but back on Cistercian land with Cistercian monks returning it to sacred space," Father Schwan said on a recent chilly afternoon, standing just inside one of the arched entrances, his voice resonating off the limestone walls and vaulted ceilings. "I look at this, and it's remarkable we've come this far, that this is actually all put back together."

With two-thirds of the original stones and modern earthquake-resistant reinforcements, Óvila's chapter house now sits, perhaps incongruously, in an open field near the abbey's modest church and vineyards, a couple of hours north of Sacramento.

It was in 1167 that King Alfonso VIII of Castile founded Santa Maria de Óvila in the province of Guadalajara, an area that he had reconquered from the Moors and that he hoped to populate with Christian settlers. For centuries, the monastery thrived as a home to Cistercian monks, a Roman Catholic order that hewed to the sixth-century Rule of St. Benedict and its emphasis on self-sufficiency, manual labor and prayer.

The monastery declined, however, and by the time it was shuttered by the Spanish government in 1835, there were only four monks left. The monastery fell into disrepair — the chapter house was being used as a manure pit — and was forgotten until it caught the eye of Hearst's art dealer, Arthur Byne, in 1930.

Hearst, the larger-than-life newspaper publisher who inspired "Citizen Kane," had already built Hearst Castle on California's Central Coast, complete with the facade of an ancient Roman temple he had bought in Italy for his estate's Neptune Pool. But Hearst was looking to build something even bigger near Mount Shasta, in the forest about 120 miles north of Vina, where his mother's summer home, called Wyntoon, had recently burned down.

Hearst wanted to build an eight-story medieval castle facing the McCloud River, and parts of the Spanish monastery would fit right in. According to American Heritage magazine, Spanish farmers and laborers from surrounding villages were hired to dismantle and haul the monastery's most important buildings. A rail track was laid, and roads and a bridge were built to transport the massive stones. Eventually, 11 ships containing much of the monastery arrived in San Francisco.

But Hearst, whose fortune was dented during the Depression, ultimately abandoned the project and gave the monastery to San Francisco. The city's plans to use it as part of a museum of medieval art in Golden Gate Park went nowhere. The crates containing the stones caught fire in the park a couple of times, and the stones were left to the elements.

In 1979, an art historian, Margaret Burke, participated in San Francisco's last attempt to restore the monastery. For four years, Ms. Burke inspected the stones to determine what could be saved.

"I found that the chapter house was the only building that would be feasible to rebuild," Ms. Burke recalled.

The city, though, could not raise the money for the project.

Over the decades, the monks here had watched the situation with growing despair. A chapter house serves as the heart of an abbey, the place where monks gather daily for readings and meetings. What's more, Cistercian architecture, in its simplicity and austerity, was a reflection of the order's faith.

"Our architecture was considered part of our prayer, and it still is," Father Schwan said. "It's not just the matter of a building. It expresses that vision of what we desire to strive for in our relationship with God."

After years of lobbying, the monks in 1994 persuaded San Francisco to give them the stones on the condition that they begin the restoration work within a decade.

It was not easy. Like other Cistercian abbeys in developed nations, this one was losing members. When Father Schwan, now 56, entered the monastery here in 1980, there were 35 to 37 monks. Now there are 22, with half of them 80 or older.

"When I entered, there were two people buried in the cemetery," he said. "We've got 16 or 17 in the cemetery today. I've actually helped bury every one of those monks, except one."

Workers broke ground on the reconstruction in 2004, and the monks eventually raised $7 million for the project. A couple of years ago, the monks also teamed up with Sierra Nevada Brewing, in nearby Chico, to produce a series of premium Trappist-style beers called Ovila. To cut down on costs, the monks chose to buy limestone from Texas instead of Europe to supplement the original stones.

Though the monks are working to raise an additional $2 million to put the finishing touches on the restoration, they are already able to use the chapter house the way their Spanish predecessors did.

That was not the fate of the other 12th-century Cistercian monastery that Hearst, ever the voracious collector, had dismantled and shipped from Spain in 1925. That monastery, St. Bernard de Clairvaux, ended up gathering dust in a warehouse in Brooklyn because of Hearst's declining fortune. After Hearst died in 1951, St. Bernard de Clairvaux's stones changed hands a couple of times before ending up in North Miami Beach, where the reassembled monastery buildings now serve as an Episcopal parish and tourist attraction.

Under the new city policy, most public hospital patients will no longer be able to get more than three days' worth of narcotic painkillers like Vicodin and Percoset. Long-acting painkillers, including OxyContin, a familiar remedy for chronic backache and arthritis, as well as Fentanyl patches and methadone, will not be dispensed at all. And lost, stolen or destroyed prescriptions will not be refilled.

City officials said the policy was aimed at reducing the growing dependency on painkillers and preventing excess amounts of drugs from being taken out of medicine chests and sold on the street or abused by teenagers and others who want to get high.

"Abuse of prescription painkillers in our city has increased alarmingly," Mr. Bloomberg said in announcing the new policy at Elmhurst Hospital Center, a public hospital in Queens. Over 250,000 New Yorkers over age 12 are abusing prescription painkillers, he said, leading to rising hospital admissions for overdoses and deaths, Medicare fraud by doctors who write false prescriptions and violent crime like "holdups at neighborhood pharmacies."

But some critics said that poor and uninsured patients sometimes used the emergency room as their primary source of medical care. The restrictions, they said, could deprive doctors in the public hospital system — whose mission it is to treat poor people — of the flexibility that they need to respond to patients.

"Here is my problem with legislative medicine," said Dr. Alex Rosenau, president-elect of the American College of Emergency Physicians and senior vice chairman of emergency medicine at Lehigh Valley Health Network in Eastern Pennsylvania. "It prevents me from being a professional and using my judgment."

While someone could fake a toothache to get painkillers, he said, another patient might have legitimate pain and not be able to get an appointment at a dental clinic for days. Or, he said, a patient with a hand injury may need more than three days of pain relief until the swelling goes down and an operation could be scheduled.

Dr. Rosenau said that the college of emergency physicians had not developed an official position on the prescribing of painkillers in emergency rooms and that he appreciated Mr. Bloomberg's activism in the face of a serious public health problem. But he said pain clinics in states like Florida and California, states where prescription drug abuse is rampant, as well as the household medicine cabinet, were probably a more common source of unneeded painkillers than emergency rooms.

City health officials said the guidelines would not apply to patients who need prescriptions for cancer pain or palliative care, and drugs would still be available outside the emergency room. They said that in this era of patient-satisfaction surveys, doctors were often afraid to make patients unhappy by refusing drugs when they are requested, and the rules would give those doctors some support when they suspected that a patient might be faking pain to get drugs.

"There will be no chance that the patients who need pain relief will not get pain relief," said Dr. Ross Wilson, senior vice president and chief medical officer of the Health and Hospitals Corporation, which runs the city's public hospitals.

Similar rules have been adopted in Washington State and Utah. Dr. Thomas A. Farley, the city's health commissioner, said opioid painkillers were not much different from highly addictive and more taboo street drugs like heroin. He called them "heroin in pill form."

More than two million prescriptions for opioid painkillers are written in New York City each year, the equivalent of a quarter of the city's population, Dr. Farley said, and about 40,000 New Yorkers are already dependent on painkillers and need treatment. Painkillers were involved in 173 accidental overdose deaths in New York City in 2010, a 30 percent rise from five years earlier.

Officials could not say how many prescriptions were written at emergency rooms. Libby Holman, a spokeswoman for Purdue Pharma, which manufactures OxyContin, declined to comment.

Dr. Farley said the city lacked the regulatory authority to impose the new guidelines on its 50 or so private hospitals. But several private hospitals, including NYU Langone Medical Center in Manhattan and Maimonides Medical Center in Brooklyn, said they would adopt them voluntarily.

Dr. Hillary Cohen, medical director of emergency medicine at Maimonides, said that even now, OxyContin was rarely prescribed in the emergency room.

So it was something of a moment when a jaunty Gov. Jerry Brown strode before cameras here on Thursday to present his budget for 2013-14.

"The deficit is gone," Mr. Brown proclaimed, standing in front of an array of that-was-then and this-is-now charts that illustrated what he said were dramatic changes in California's fortunes.

"For the next four years we are talking about a balanced budget," he said. "We are talking about living within our means. This is new. This is a breakthrough."

Mr. Brown was not just talking about a balanced budget. He projected that the state would begin posting surpluses starting next year, leading to a projected surplus of $21.5 million by 2014, a dramatic turnaround from the deficit of $26 billion — billion, not million — he faced when he was elected in 2010.

The governor said California's finances were strong enough that he wanted to put aside a $1 billion reserve fund to guard against future downturns, and included in the budget sharp increases in aid to public schools and the state university system, both targets of big spending cutbacks.

The change in fortunes reflected cuts that were imposed over the past two years, a temporary tax surcharge approved by voters in November that expires in seven years, and a general improvement in the state's economy.

Mr. Brown's balanced budget projection was more optimistic than one put out by an independent legislative watchdog in November, and he pointed to a series of factors, including severe cuts in federal assistance, that could push California back into difficulty.

Yet it was the latest indication that the state appeared to be turning around. Even the less upbeat report by the watchdog group, the Legislative Analyst's Office, said the state was facing a deficit of just $1.9 billion, which seems almost pocket change after the $26 billion projected deficit the state once confronted.

Mr. Brown's news was hailed on both sides of the political aisle. "This is a proposal that clearly shows California has turned the corner," said John A. Pérez, a Democrat who is the State Assembly's speaker.

Connie Conway, the Assembly's Republican leader, said it was "good news for taxpayers that the state has made progress in getting our financial house in order."

"But we haven't fully solved our budget problems just yet," she said.

The budgetary distress has meant that, for years, the Legislature has battled over what to cut or, in some cases, what kind of maneuvers might be appropriate to avoid cuts. Good news or not, the announcement means that more, albeit different, kinds of battles were in the offing, lawmakers and Mr. Brown said.

Democrats now control two-thirds of the Assembly and Senate, and some of them have talked about restoring at least some of the social service cuts, like dental care for the poor, that were imposed to bring the state to this point, Mr. Brown said he understood the impulse to repair broken social services, but he warned against returning to a boom-and-bust pattern of spending during the good years, only to later struggle through debt.

"We have to live within the means we have; otherwise we get to that situation where you get red ink and you go back to cuts," he said. "I want to avoid the booms and the bust, the borrow and the spend, where we make the promise and then we take back."

Mr. Brown, who has always presented himself as something of a moderate in his party, suggested that in the months ahead, he would be an enforcer.

"It's very hard to say no," Mr. Brown said. "And that basically is going to be my job."

On that point, Mr. Brown found an unlikely ally in Ms. Conway. "Now is not the time to enact massive spending increases that will reverse the progress we've made in reducing the deficit," she said.

On another contentious front, while Mr. Brown proposed a significant increase in school spending — $2.6 billion — he said he wanted a financing formula that would direct more money to poor students. Lawmakers said that could set off a fight between wealthier and poorer districts.

Mr. Brown, in presenting his budget, suggested that the turnaround should be a rebuke to "a couple of characters" who have "written off California as a failed state," a reference to conservative commentators who have, for a year, questioned the state's economic policies and its very future.

Now, Mr. Brown said, he wanted the nation to look to California, and to his example. He promised a combination of "fiscal discipline and imaginative investment" to complete the state's restoration.

"I would like to do something that would make California a leader and an example of what America has to do," he said.

The money-saving steps, announced Thursday by Defense Secretary Leon E. Panetta, are designed to be reversible should a compromise be reached to avoid automatic reductions in federal spending set to begin in March. The Pentagon's share could be up to $500 billion in cuts over 10 years.

To prepare for "this extraordinary budget uncertainty that we're confronting, the leadership of this department has decided that it must begin to take steps in the coming weeks that would reduce the potential damage that we would face should Congress fail to act to prevent the cuts," Mr. Panetta said.

Specific steps were outlined in a memo distributed across the military and civilian departments and signed by Ashton Carter, the deputy defense secretary, and included curtailing nonessential travel, training and conferences.

The effort is designed to not degrade the war effort in Afghanistan. Services for families of military personnel also were protected, even as the military and civilian departments were ordered to continue planning for even deeper cuts.

"Sequestration is a self-inflicted wound on national security," said Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, using the technical term for automatic cuts. "It's an irresponsible way to manage our nation's defense. It cuts blindly and it cuts bluntly. It compounds risk, and it compromises readiness."

Supervisors have so far found 26 cases in which the technician failed to detect biological evidence when some actually existed, according to the medical examiner's office. In seven of those cases, full DNA profiles were developed — crucial evidence that sex-crime investigators did not see for years, hampering their ability to develop cases against rape suspects.

In one of those instances, the newly discovered DNA profile matched a convicted offender's sample, leading to an indictment a decade after the evidence was collected, according to Dr. Mechthild Prinz, the director of forensic biology at the medical examiner's office.

In two other instances, the new DNA profiles were linked to people either already convicted or under suspicion.

The scope of the problem has yet to be determined; at several points, supervisors in the medical examiner's office thought they had gotten to the bottom of the technician's errors, which has been under internal investigation since March 2011, only to find that the trail went further, leading to more cases that had to be reviewed.

"This is the first time we've had anything like this," said Ellen Borakove, a spokeswoman for the office of the chief medical examiner.

The office has been at the forefront of forensic technology; its work after the Sept. 11 terrorist attacks and in trying to name the unidentified dead in the city's potter's field has been hailed widely. The office is now advocating for the acceptance of so-called low copy number DNA — sometimes transmitted only by a touch — as a way to link suspects to a crime.

But the continuing review of the technician's cases underscores how DNA evidence, widely perceived as being nearly irrefutable proof of guilt or innocence, can still be subject to human error.

Each time there is an accusation of a sexual attack, investigators try to recover DNA evidence from saliva, semen or blood that may have been left by the assailant. The task of recovering such evidence — known as a rape kit — falls to the medical examiner's office, which currently employs 48 technicians who conduct preliminary tests on the kits.

The technician, who resigned in November 2011, had two responsibilities when processing rape kits: She had to snip cuttings from swabs taken from victims' body at the hospital, and place them in test tubes for DNA analysis by more experienced lab workers.

She also inspected the victims' clothing, usually underwear, for stains that might indicate the presence of DNA. Sometimes she overlooked stains, the review found. At other times, she identified stains, but then botched the chemical test used to detect semen and reported finding nothing, laboratory officials said.

The errors, Dr. Prinz said in an interview, involved reporting false negatives, not false positives. "We do know that nobody was wrongfully convicted," she added.

But in the course of reviewing the technician's work, supervisors quickly discovered another problem. Sixteen pieces of evidence, generally swabs contained in sealed paper envelopes, were found in the wrong rape kit, commingling DNA evidence from 19 rape investigations, according to a letter from the medical examiner's office.

"Our guess is the technician had both kits open at the same time, and when she was reassembling the case files, evidently she had misplaced the evidence items from one kit to another," Eugene Lien, a quality assurance manager with the medical examiner's office, told a state oversight board last year. It was not "standard policy at all," he added, for a technician to have two cases open at once.

Asked in an interview about the risk of cross-contamination, Dr. Prinz said: "It's extremely unlikely. I don't think that is a risk."