Chanel Lewis, 20, was arrested and charged with second degree murder after the medical examiner's lab matched DNA evidence from the crime scene and Vetrano, to the suspect, police said.
UPDATED STORY: What we know about Chanel Lewis, Karina Vetrano's suspected killer
It was an emotionally explosive arraignment Sunday in Queens as the Vetrano family unleashed months of agony and fury at the defendant's family.
DNA was recently obtained from Lewis through a voluntarily cheek swab. It was taken previously from under Vetrano's fingernails, behind her ear and on her cell.
Lewis, who does not work, has no prior arrests. He lives in East New York with his mother, and police said they do not believe he was stalking or knew Vetrano.
Police say officials saw Lewis around his neighborhood on the Brooklyn/Queens line back in May, and thought he was suspicious. The next day, sources say there was a 911 call about Lewis, because he looked like he was about to break into a property with a crowbar. Last week, Lewis was considered as someone police should consider in Vetrano's murder. Police found a summons, tracked Lewis down, and he took a voluntary DNA swab on Thursday. On Saturday afternoon, the Medical Examiner's officer reported a match with his DNA at Vetrano's crime scene.
Detectives took him into custody Saturday and they said he was interviewed by detectives and made detailed confessions. Right now, sources say there is no motive, other than Lewis was 'unhinged,' and was apparently upset there were so many people in the apartment where he lived with his parents.
WATCH THE FULL NYPD NEWS CONFERENCE ON THE ARREST:
Despite having no arrests, Lewis received three court summonses in 2013. Boyce said in the last 10 days, police developed a profile for him.
"Karina helped us to identify this suspect, thanks the DNA we recovered from under her nails."
Vetrano's parents spoke out Thursday, trying to renew momentum in the case on the six-month anniversary of the murder.
Vetrano, 30, left her home for a jog around 5 p.m. on Aug. 2. When she failed to return, family members reported her missing and started searching for her.
Vetrano's body was found around 9 p.m. by her father about 14 blocks from her home, in the marshes of Spring Creek Park, off 161st Avenue and 78th Street. She was about 15 feet off the trail.
The medical examiner's office performed an autopsy and ruled Vetrano's death a homicide, saying she was strangled.