A man suspected of punching a passenger on a New York subway platform — watching the unconscious man's head being hit by an oncoming train — and then punching him again has surrendered to the police.

The incident took place on Union Square subway platform at about 2:50 a.m. on Dec. 16, when artist Francis Michael Christie was attacked by 24-year-old Benjamin Gonzalez and another man who is yet to be identified.

Gonzalez, a Queens resident, surrended last Wednesday, authorities said. The second alleged attacker is yet to be apprehended, and was described only as an Asian man.

Forty one-year-old Christie shattered his skull and is being treated at Bellevue Hospital.

According to a report in the New York Daily News, Christie, an artist from Flatbush, Brooklyn, was punched by Gonzalez and the unidentified man, which left his head hanging over the ledge of the platform.

An oncoming train hit Christie, shattering his head. Prosecutors said Gonzalez then pulled Christie back from the ledge and hit him in the head again.

Gonzalez and the other suspect were caught on surveillance camera inside the subway station following the attack, officials said.

According to the court records, Gonzalez was charged with assault and reckless endangerment. However, he appears to have been released after posting $75,000 bail, reported the New York Daily News.

Christie’s mother, 65-year-old Joy Wells, on Sunday said she was happy that the suspect was under arrest.

She told the New York Daily News, “I was elated. I figured that in New York there are 8 million people, they’ll never find him. I didn’t think there would be an arrest for a very long time.”

Wells further said, “The detectives just told me they made an arrest, and after that my mind kinda went blank.”

Talking about her son’s health conditions, she said that Christie was recovering slowly, and on Friday was shifted to a rehabilitation unit from the intensive care unit.

She said, “He’s up walking. They’ve had him going up some steps. But he’s still not talking.”

Wells remains hopeful that her son will make that he will make a full recovery.

“He didn’t have his phone for three weeks,” she said.

“He wanted his phone and they took it to him, and he remembered the password.”

Wells had spoken to Christie, a few days before the incident took place. She recalled that her son was very excited about his upcoming art show in Greenpoint where he was to display a number of new paintings, some of them made using a new chrome pen.

She added, “I was excited for him. I couldn’t wait ’til he called me after the show to see how people reacted to his work.”