Grand jury may review NYC subway chokehold killing: Sources

The case involving the death of a homeless man on a New York City subway is likely headed to a grand jury next week, law enforcement sources said.

The investigation into Neely's death is ongoing. A grand jury would determine whether criminal charges are warranted, according to the sources.

Detectives have interviewed more than six witnesses and are still looking to talk to several more. Police sources told ABC News Neely had not become violent and had not been threatening anyone in particular.

Neely, a homeless man, was killed by another New York City subway passenger who held him in a chokehold for several minutes, according to witnesses and police. Neely had allegedly been yelling before being subdued by the other passenger, police said. The man seen restraining Neely told police he was not trying to kill Neely.

The 24-year-old man pictured with Neely in a chokehold has been identified as Daniel Penny. Attorneys for Neely's family told ABC News police have confirmed Penny's identity to them.

In a new statement Friday night, attorneys for Penny offered "condolences to those close to Mr. Neely."

The attorneys also claimed "Mr. Neely began aggressively threatening Daniel," and that the Marine veteran and others "acted to protect themselves."

Police confirmed Neely lost consciousness after the physical struggle. Neely was rushed to Lenox Hill Hospital, where he was pronounced dead.

Neely's death has been ruled a homicide by the medical examiner's office. The 24-year-old involved in the incident has not been charged.

According to police sources, Neely had a documented mental health history. He had been arrested more than 40 times prior for assault, disorderly conduct and fare evasion.

The NYPD has issued a call for public help as investigators review video footage and other material, urging anyone who saw or has any information about this matter to contact Crime Stoppers at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782).

The Manhattan DA's office encourages anyone who witnessed the incident or might have information to also call 212-335-9040.

ABC News' Matt J. Foster contributed to this report.