Grand jury indicts Daniel Penny in chokehold death of Jordan Neely

A grand jury has indicted former U.S. Marine Daniel Penny in connection with the chokehold death of Jordan Neely aboard a subway train.

The exact charges will not be unsealed until Penny appears in court at a later date, the sources said. Penny was initially arrested on a second-degree manslaughter charge.

Video showed Penny, 24, putting Neely in a chokehold on May 1. Several witnesses observed Neely making threats, assistant district attorney Joshua Steinglass told the judge.

Some witnesses told police that Neely was yelling and harassing passengers on the train, authorities said. Police sources told ABC News that Penny was not specifically being threatened by Neely when he intervened and that Neely had not become violent and had not been threatening anyone in particular.

Neely was homeless at the time of the incident.

Penny held Neely for several minutes, and at some point Neely stopped moving, but Penny continued to hold him for a period of time, Steinglass said. Penny remained on the scene to talk with police following the incident, Steinglass said.

The medical examiner determined Jordan Neely was killed by a chokehold and his death was ruled a homicide.

Steinglass said prosecutors conducted a "thorough investigation" that included interviews with eyewitnesses, 911 callers and responding officers before moving forward with the criminal charge. Penny turned himself in to police on May 12 following an announcement from the Manhattan district attorney's office regarding charges. He has not yet entered a plea.

Neely, who was homeless at the time of his death, had a documented mental Health History, according to police sources. Neely had been previously arrested for several incidents on the subway, though it's unclear how many, if any, led to convictions.

Attorneys for Neely's family said in a statement the "indictment is the right result for the wrong he committed."

"The grand jury's decision tells our city and our nation that 'no one is above the law' no matter how much money they raise, no matter what affiliations they claim, and no matter what distorted stories they tell in interviews," the attorneys said in a statement.

Attorneys for Penny released a statement Wednesday evening stating it respected the grand jury's decision and it "should be noted that the standard of proof in a grand jury is very low."

"We're confident that when a trial jury is tasked with weighing the evidence, they will find Daniel Penny's actions on that train were fully justified," attorney Steven Raiser said in a statement.

"We're all saddened at the loss of human life," Penny's attorney Thomas Kenniff said in a statement. "Daniel Penny saw a genuine threat and took action to protect the lives of others."

Mayor Eric Adams released a statement Wednesday afternoon stating he appreciated Manhattan District Attorney Alvin Bragg "conducting a thorough investigation into the death of Jordan Neely."

"Like I said when the DA first brought charges, I have the utmost faith in the judicial process, and now that the grand jury has indicted Daniel Penny, a trial and justice can move forward," the mayor said in his statement.

The Rev. Al Sharpton, who eulogized Neely at his funeral, released a statement reiterating his calls for a thorough prosecution of Penny.

"The National Action Network has stood in support of Jordan's family since day one. This was a clear-cut case of vigilantism that has no place in our society, which is why I spoke against it at Jordan's funeral," Sharpton said in his statement.

ABC News' Stephanie Wash and Ivan Pereira contributed to this report.