Nicholas D'Agostino, 20, plead not guilty to charges related to a fatal shooting on a LIRR train in Ronkonkoma in 2022. NewsdayTV's Cecilia Dowd reports.  Credit: Newsday/Howard Schnapp; James Carbone; Tom Lambui

A Yonkers man who allegedly shot his friend twice “execution style” while they were alone on a parked overnight LIRR train in Ronkonkoma last year pleaded not guilty to second-degree murder at his arraignment Friday. 

Nicholas D’Agostino, 20, was arrested in Yonkers Wednesday, 15 months after the Feb. 16, 2022, slaying was captured by MTA surveillance video, police said.

The victim, Yusef Staine, 20, of West Babylon, was pronounced dead at the scene, officials said.

“[D’Agostino] shot Yusef Staine in the back of his head as he walked behind him in the train car,” Assistant Suffolk County District Attorney Elena Tomaro told Acting Suffolk Supreme Court Justice Steven Pilewski in Riverhead. “When Mr. Staine collapsed to the ground, [D’Agostino] put another round into his torso.”

Suffolk County District Attorney Ray Tierney said Friday that Staine became a suspect soon after the shooting, as investigators obtained search warrants for digital data and reviewed “hundreds of hours of video footage.” That footage included the shooting itself, which prosecutors shared with the media Friday.

“This investigation was extensive,” Tierney said, adding that it included contributions from both Suffolk Police and investigators with the MTA, whose work the district attorney described as “invaluable.”

Tierney said D’Agostino used a ride share app to leave Ronkonkoma and took a Greyhound bus out of Port Authority terminal in New York City nearly 24 hours later.

Yusef Staine, 20, of West Babylon, was fatally shot in...

Yusef Staine, 20, of West Babylon, was fatally shot in February 2022. Credit: Family photo

Tomaro described the two men as friends, saying D’Agostino had traveled from Phoenix to visit Staine on Long Island three days earlier.

Tierney said investigators are still working to establish a motive.

He declined to elaborate on how they were friends or details about how they met. Prosecutors said D’Agostino had “some roots” on Long Island.

What investigators could piece together from MTA footage is that the two men traveled together to New York City with two other friends on Feb. 15.

They were returning alone to Wyandanch when they missed their stop in the early morning hours of Feb. 16. The two friends then boarded a westbound train that hadn’t yet left Ronkonkoma, where the shooting occurred shortly before 2 a.m. No other passengers were on board.

In the video from the train car, the man prosecutors say is D’Agostino paces around, keeping an eye on a bathroom door as he sits down and pops back up several times.

The alleged shooter, his face covered by a ski mask and his left hand gloved, sits down one last time as Staine returns from the bathroom. The two exchange words for about 30 seconds, with the shooter occasionally gesturing with his hands as if he is possibly arguing with Staine.

Seconds before he is shot, Staine hands his traveling companion what Suffolk County Police Commissioner Rodney K. Harrison said is “a bag of chips.”

As they walk away, the man described as D’Agostino reaches into his waistband with his left hand and pulls out a handgun. He exits the train after the second shot is fired as blood slowly spills onto the floor.

“Justice,” one woman loudly chimed twice as Staine’s family left the arraignment Friday. Staine’s mother wore a T-shirt with his photograph on it under a red blazer. She declined to speak with reporters.

D’Agostino’s court-appointed attorney, George Duncan of Central Islip, said his client has no criminal history and he has not yet reviewed any evidence or discussed the case with him at any length.

D’Agostino, who was remanded to the county jail without bail, is facing 25 years to life if convicted of the murder charge. He is charged with two counts of criminal possession of a weapon, which could increase his sentence to 40 years to life, Tomaro said.

The shooting was the first killing on an Long Island Rail Road train in nearly 30 years, after a 1993 rampage by gunman Colin Ferguson killed six people at the Merillon Avenue Station and injured 19 others.

Tierney said he wished to underscore that last year’s shooting was an isolated incident and “the LIRR is safe.”

D’Agostino is due back in court June 14.

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