(NewsNation) —  Daniel Penny, who faces charges in connection to the chokehold death of Jordan Neely on a New York City subway train, was in court Thursday morning for a pre-trial hearing.

The Marine veteran has pleaded not guilty to second-degree manslaughter and criminally negligent homicide charges. If convicted, Penny faces up to 20 years in prison.

Back in January, the defense filed a motion to dismiss the charges, but a judge denied the request.

On May 1, the New York Police Department reported that Neely, a street performer who had been experiencing homelessness, boarded the F train in Manhattan and began acting erratically. Penny claims Neely was angry and talking to himself, which prompted him to intervene. Neely was unarmed, and reportedly asking for food as well.

Cellphone footage from those on the train shows Penny putting Neely in a chokehold and holding him down until he stopped moving and breathing. Officers arriving to the scene reported Neely was unconscious and he was taken to a nearby hospital, where he was pronounced dead.

A medical examiner ruled Neely’s death a homicide due to “compression of neck.”

In court Thursday, defense lawyers and the prosecution went over what evidence would be admitted during the trial. The judge has told both sides he’s not going to rule on this matter until he hears all the evidence.

Police officers who responded to the scene testified about what it was like. A video interview with Penny and the NYPD was shown to the courtroom. During the video, Penny says Neely ripped off his windbreaker, threw it and threatened people on the train.

Attorney Donte Mills, who is representing Neely’s family, previously told “Dan Abrams Live” that Penny had “no authority” to place someone in a chokehold. Mills said Penny was not attacked by Neely.

“(Penny) knew or should have known that choking him (Neely) for 15 minutes would kill him,” Mills said. “I can’t tell you what was in his mind when he approached him.”

Penny’s attorneys said their client “never intended to harm” Neely and that he was just trying to protect others.

Prosecutors are asking the judge to ban testimony that includes Neely’s psychiatric history and K2 abuse, arguing it would unfairly damage his reputation and that information is irrelevant. Defense attorneys, however, say it is “crucial” for the jury to understand Neely’s behavior, and the justification for Penny’s action.

Jury selection in the trial is set to begin Oct. 21.

NewsNation digital producer Caitlyn Shelton contributed to this report.