New York City is building a vast, unregulated DNA database that police are already using to connect suspects to evidence from crime scenes across the five boroughs.

In the last five years, the number of DNA profiles in New York’s local database has grown dramatically, and by an ever-increasing rate, driven in part by a push to collect DNA in every gun case. As of July, the Office of Chief Medical Examiner was storing about 64,000 genetic profiles, The Trace and WNYC have learned.

Details about the size of the database and its rapid growth have not been previously reported.

The DNA in the database comes largely from crime scenes and suspects at a time when it is increasingly easy to obtain a profile from just a few cells left on a water bottle or doorknob. Lawyers say there are people in it who have never been convicted of a crime, and have no idea that their genetic profiles are routinely checked against evidence collected in criminal investigations.

New York police say database hits generate thousands of solid investigative leads a year, and are a major way they nab dangerous criminals. “DNA is probably the most powerful scientific tool available to us,” said Emanuel Katranakis, commanding officer of the NYPD’s forensic investigations division.

Forensic and legal experts agree that DNA evidence is a powerful crime-solving tool. But some have voiced alarm at the way New York City has built its database — with no oversight or scrutiny. State and federal DNA databases, by contrast, are subject to legislative oversight and strictly limit whose DNA can be stored, in most cases, to people who have been convicted of crimes.

Experts are also concerned that there appears to be no clear mechanism to scrub the database of DNA from people who give samples voluntarily, or whose DNA is taken without their knowledge.

“It always is extremely troubling when bureaucracies spiral out of control and start invading areas that the state legislature did not authorize, and which are impinging upon privacy concerns,” said Barry Scheck, co-founder of the exoneration group the Innocence Project. Scheck said he complained many times about New York City’s unregulated “rogue” database during his years on the New York State Commission on Forensic Science.

Last year, police investigating the killing of a Howard Beach jogger, Karina ­Vetrano, collected DNA from more than 150 people to compare with material found under the victim’s fingernails, and on her neck and cellphone, court records show. One of those people was later charged with the murder. The DNA from many of the others was labeled “suitable for entry” into the city’s database — meaning that, although those people were never charged, their DNA can remain on file indefinitely and be run thousands of times a year against biological material found on victims and evidence. Police wouldn’t say how they identified the people whose DNA was collected. The Medical Examiner’s Office declined to comment.

One important group has stayed out of New York’s growing database: rank-and-file police officers. Though some forensic experts say it would be best to keep all officer profiles on file to eliminate their DNA when it winds up at crime scenes, only crime scene specialists, police lab employees, and bomb squad officers provide DNA. “Contractually police officers are not required to give DNA samples,” an NYPD spokesman said in an e-mail.

Experts say it’s essential that local governments protect their citizens by making clear rules about how biological evidence should be collected, stored, used, and discarded.

I think DNA is a powerful tool for law enforcement and crime solving,” said Erin Murphy, a New York University law professor and author of Inside the Cell: The Dark Side of Forensic DNA. “[But] the standards governing who has to give DNA, and what happens to that DNA once they’ve given it should really be very particularly determined in law — not at the whim of a prosecutor or a police investigator.”

New York’s medical examiner has maintained a DNA database since the late 1990s. Initially, DNA could only be collected if a substantial amount of genetic material was found, like blood at a crime scene. It was typically used to investigate violent crimes. More recently, scientists learned to pull a DNA profile from just a few cells on something a person touched.

The ability to make DNA matches from tiny amounts of genetic material has proved a boon to authorities trying to address a particularly vexing problem: stubbornly low conviction rates in gun-possession cases.

As The Trace and WNYC reported in July, the NYPD is the first major police department in the country to swab virtually every gun that officers recover for DNA. This push is a big reason for the rapid growth of the city’s DNA database.

Last year, the medical examiner’s office performed DNA tests on 1,682 guns — four times as many as two years before. Police matched 309 firearms to suspects — six times as many hits as two years before.

Prosecutors credit the program with helping them secure convictions in 56 percent of the gun-possession cases in the first half of this year, a higher percentage than at any time in the last decade.

David Kennedy, a policing expert at John Jay College of Criminal Justice, said that collecting DNA from everyone who has touched an illegal gun in New York could be a powerful tool for police, since there is overlap between that group and people likely to be involved with other crimes.

“It’s going to build on itself, and be more and more useful over time,” Kennedy said.

State and federal officials are also building out DNA databases, but there are strict rules about what genetic material can be entered.

Convicts, people awaiting trial, and detained immigrants are required to submit a DNA sample to the Federal Bureau of Investigation, which maintains the federal database. Before new collection practices are adopted, Congress holds hearings and there is a public debate.

State guidelines vary, but are also openly debated and approved by elected officials. In New York, lawmakers approve the parameters for the state database.
Many local databases have only self-imposed rules for whose DNA can be entered. A spokeswoman for New York’s medical examiner said her office has created guidelines for the database “developed in accordance with state and national laws,” but they are not publicly available. She would not share them with The Trace and WNYC.

New York police said it isn’t their aim to sweep innocent people into the database.

“We’re not looking to collect DNA from all persons,” Katranakis said. “We’re very keen on making certain we’re always respecting the constitutional rights of New Yorkers, that’s paramount.”

Scheck, the Innocence Project co-founder, said that in his two decades on an accrediting panel for the state he grew increasingly concerned about the New York City medical examiner’s reluctance to put database rules in writing.

He would ask the office, for example, if it put rape victims’ DNA in the database. He was told no, he said.

“I said ‘Well great! You shouldn’t! But where’s that written down? Where’s your set of rules and regulations?’”

“I personally never saw them,” Scheck said.

DNA science isn’t perfect. Experts say as police use it more in investigations, they will get more legitimate hits. They will also have more mix ups and false positives.

Terrell Gills was charged with robbing a Dunkin’ Donuts in Queens after a trace amount of his DNA was found on the store’s cash register. It was one of three similar Dunkin’ Donuts robberies in the same week. Another man was arrested for the two other crimes, pleaded guilty, and is serving nine years in prison. Because of Gills’ DNA hit, he spent 18 month on Riker’s Island before he was acquitted at trial. He doesn’t know how his DNA could have gotten on that register, but said he used to go to that store occasionally with his 6-year-old daughter.

The New York medical examiner’s office has also been criticized for pushing the limits of science too far. A coalition of defense lawyers recently asked the state inspector general’s office to investigate two testing methods that the medical examiner stopped using in January.

Experts say we may not yet have imagined all the ways our genetic material might be misused. Government employers might use it to predict future illnesses and diseases. They might use it to track down a whistleblower.

Some of the tactics law enforcement officers use to get DNA samples have also been questioned.

In New York, defense lawyers regularly fight cases in which police take their clients’ DNA without them knowing — for example, by collecting it from a glass of water accepted while being questioned in a precinct. Under the law, that DNA is considered abandoned property, similar to items a person throws in the garbage. Defense lawyers argue that their clients didn’t abandon their genetic material. They don’t have the option of taking it with them.

Ashley Burrell, an attorney with the public defense group the Bronx Defenders, described a case in which one of her clients was acquitted in a gun-possession case — in part because his DNA, which police got off a cigarette he had smoked in the precinct, did not match the DNA on the gun. But the same DNA that helped her client beat the charge will be analyzed every time police are investigating a crime in which biological material was recovered, Burrell said.

“He feels like a forever suspect,” she said.

In a Brooklyn gun case, a judge threw out evidence after he found that police had been practically “holding a defendant hostage,” in a police precinct for 13 hours until he agreed to give a DNA sample.

“He was just so exhausted,” Rebecca Kavanagh, the Legal Aid lawyer in that case, said of her client. “He’d been interviewed four times. It just got to the point where he had just had it.”

In other places, police building local DNA databases have been even more aggressive. In several Florida towns police ask people for DNA during routine stops. In Orange County, California, prosecutors regularly offer non-violent offenders the option of having the charges against them dropped in exchange for giving their DNA.

Lawyers in New York now routinely ask judges to grant protective orders to keep a client’s DNA out of the database until a case concludes, or if the client is found not guilty or the charges are dropped. Some judges agree, others don’t.

But when police take people’s DNA without their knowledge, there is no clear legal path for the subjects to get their DNA removed — or even to find out it is in there in the first place. There is also no set protocol for getting a person’s DNA out of the database when they give it to police voluntarily.

In New York and most other large cities, police officers are not required to provide DNA samples unless a judge orders them to.

Terrence Dwyer, a lawyer who represents police officers and writes about legal issues and law enforcement for the policing news website, said he doesn’t think officers should have to give samples to the database. But nor does he think anyone else should, unless they’ve been convicted of a crime.

“I don’t trust them to do the right thing with it,” Dwyer said of governments that employ police officers and would store their DNA. “Are we now in this Orwellian future where everyone’s going to have a bar code? Your DNA should only be in a database if you’re convicted of a crime.”