A day after a retired correction officer fatally shot a fellow subway rider, police have made an arrest. The victim's friend, Joscelyn Evering, 28, was charged with assault and menacing.

On Tuesday night, around 6:30 p.m., Will Groomes, 69, had been on a 4 train when he apparently raised the ire of Evering and Gilbert Drogheo, 32. DNAinfo reported that the older man "walked in between a pair of friends having a conversation while blocking the doors... [Drogheo and Evering] took exception with Groomes for walking between them and began to make angry comments to him." A source told the Post, "The guy who got shot told the correction officer on the train, ‘I’m going to hit you so hard your children and uncle are going to feel it.'"

Witnesses described the young men as belligerent and possibly drunk and said they shoved Groomes into a subway seat, even spitting on him and punching him. When the train arrived at Brooklyn's Borough Hall station, they all got out of the train and continued to argue.

According to NBC New York, "Groomes allegedly identified himself as an officer and told Drogheo and Evering that they would be put under arrest. The source says that the men ran away, with Groomes following. As the men tried to walk out of an exit gate, Drogheo and Groomes began scuffling again. Then, the source says, Groomes pulled out a gun and fired one round, which fatally hit Drogheo in the abdomen."

Video shows Groomes and Drogheo physically fighting, and then Groomes shooting Drogheo:

It's unclear whether Groomes will be arrested. From the NY Times:

The Brooklyn district attorney’s office said on Wednesday that it was still “investigating the incident to see if a grand jury presentation is warranted.”

Neither Mr. Drogheo nor Mr. Evering was armed, the authorities said. Mr. Groomes told detectives that he had warned the men he intended to arrest them before following them through the station, his gun at his side, a law enforcement official said.

“There is an issue to be determined, which is whether Groomes was justified,” said the official, speaking on the condition of anonymity because no decision had been made on whether to charge him. “The shooting occurred after Groomes told them they had assaulted him and he was going to arrest them.”

Drogheo's uncle called Groomes a "murderer" and told the Daily News that "his nephew was an electrician who was dedicated to his work. 'He was a great kid,' the uncle said. 'All he did was work.'"

The Post notes that Drogheo has had "23 arrests dating back to when he was just 12 years old for crimes including robbery, assault and drug possession... Records show he served a five-year prison sentence for a Brooklyn holdup and was locked up for violating parole in 2012. At the time of his death, he was on probation in New Jersey for a May 2014 incident in which he punched a woman in the mouth and threatened to kill her."

Norman Seabrook, head of the correction officers' union, said that Groomes was "remorseful" about the shooting but insisted that he had been protect himself, "“He’s thankful for all the support he’s gotten. He’s done nothing wrong."

Groomes' neighbor in Clinton Hill told PIX 11, "It’s always pleasant, but never the type of guy that would go after, no… no… and if anybody tried to mess with his character, I would defend him on that. Really, honestly, truthfully, good guy. Really, really, good guy."