Seven members wanted to convict him, according to the juror, including all four white members of the panel, a Hispanic woman, an Asian man and a black man.

The five people who had doubts about his guilt were of black, Hispanic and Indian descent.

Some jurors were troubled by how Mr. Lewis, who is black, became a suspect in the first place, the juror said. He was arrested on what amounted to a hunch from a police lieutenant, who, months before the murder, had seen him “acting suspiciously” as he wandered through Howard Beach, a mostly white neighborhood where the murder happened.

The members who were leaning toward acquittal thought the police had pressured Mr. Lewis into a false confession, the juror said. Some wanted more information about what happened in the hours before his videotaped statement when he had first denied any involvement in the murder.

One of those jurors also questioned why DNA evidence had been handled by several officers before being turned over to a lab, and why Mr. Lewis’s DNA was found on Ms. Vetrano’s neck but not on her necklace.

Jurors spent at least three hours discussing the DNA evidence, the juror said. Deliberations in general were civil at first, the juror said, but at certain moments it turned hostile. “You could feel the tension in the room,” the juror said.

As talks dragged into the night of the second day, the jurors tired. They were still divided seven to five in favor of a conviction. But two jurors told the group their minds were firmly made up: Mr. Lewis was not guilty.

Image Ms. Vetrano’s badly beaten body was found on a running trail in the Howard Beach section of Queens.

The panel decided to write a letter to the judge, Michael B. Aloise of State Supreme Court, hoping that he could somehow help with the impasse, the juror said.