The Docket: DNA Evidence, Policing, and the Constitution

When 30-year-old Karina Vetrano was sexually assaulted and murdered three years ago while jogging in a Queens park, the NYPD felt intense pressure to solve the crime.

But as the case started to run cold, police allegedly engaged in a dragnet based on its DNA database that led them to 20-year-old Chanel Lewis. Lewis confessed to the crime, but later said his confession was coerced. Prosecutors tried him twice, securing a conviction the second time around in April 2019. He was sentenced to life in prison without parole.

Since then, Lewis' attorneys and critics of the NYPD have called attention to the police investigation that ended with his arrest —especially the legality of testing literally hundreds of people's DNA in quest for evidence. More than 30,000 people have signed an online petition asking the Queens District Attorney's office to investigate claims of racial bias in the investigation, and three of the seven candidates in the race for Queens District Attorney are now committing to re-examine the case if elected. An NYPD spokeswoman told WNYC that the department gathers DNA evidence in strict adherence with the law and follows established protocols. She also said the department is working with the Office of the Chief Medical Examiner to review collection and management policies and procedures around DNA evidence.

But questions remain that go beyond this one case as to how police use DNA evidence as an investigative tool. Civil libertarians have raised concerns about the methods police use to collect DNA from potential suspects, how that information is cataloged in databases, and how long that data is kept, to name a few items. NYU Law professor Erin Murphy told WNYC's Jami Floyd that while DNA evidence has the potential to be a powerful tool, it comes with big questions about accuracy and privacy.

"Law enforcement, in situations like that, at their best they use every tool in the toolbox," Murphy said. "But I think at the worst, they can start to really deform and misshape the tool box in just the hopes of solving the case any way they can."

For the full conversation, click "Listen."

The Docket is our series in which WNYC’s All Things Considered host Jami Floyd takes a deep dive into the American Legal System.