NEW YORK — A Manhattan grand jury has begun hearing evidence against former Marine Daniel Penny concerning the chokehold killing of Jordan Neely on the subway last month, the Daily News confirmed Thursday.

According to a law enforcement source, the panel began hearing the Manhattan district attorney’s case against Penny on Monday.

Penny, 24, of Long Island, has pleaded not guilty to second-degree manslaughter for the May 1 killing aboard an F train. Disturbing footage of the incident shows Penny with his arms around Neely’s neck until the 30-year-old stopped moving.

Prosecutors say Penny approached from behind, placing Neely in a chokehold while he was reportedly acting erratically and threatening straphangers. Neely got on the northbound train at Second Avenue and was unconscious when it got to the next stop at Broadway-Lafayette.

Penny, a Marine veteran who was unemployed and looking for work at the time of the incident, was taken in for questioning and released. The city medical examiner ruled Neely’s death a homicide days later.

Manhattan DA Alvin Bragg filed charges on May 11, and Penny was arraigned the next day. He’s out on a $100,000 bond.

Neely grew up in Manhattan and was known to many New Yorkers as a passionate Michael Jackson tribute artist. His relatives say he suffered deeply from mental illness and was homeless at the time of his killing.

Fox News first reported news of the grand jury’s impaneling.

Penny’s attorney did not immediately respond to a request seeking comment.