Westchester County Police charged William Johnson, 20, of Yonkers, with manslaughter for the Jan. 30, attack, said Kieran O'Leary, spokesman for Westchester County.
Johnson is accused of punching Bryce Neville, 18, of Mount Vernon, in the head, causing the man to suffer fatal injuries when he fell to the floor and struck his head, O'Leary said.
According to O'Leary, the two men had argued earlier in the day and Johson allegedly punched Bryce from behind as the men walked through a common area at the jail.
Bryce was taken to the Westchester Medical Center in Valhalla in critical condition following the attack. He died of his injuries on Tuesday, Feb. 4.
Johnson is scheduled to arraigned on Thursday, Feb. 20 in Mount Pleasant Town Court.
The arrest followed an investigation by detectives from the County Police General Investigations Unit and investigators from Department of Correction Special Investigations Unit.
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