The 83-year-old US Air Force veteran who was randomly shoved onto the subway tracks by an illegal migrant on the Upper East Side has died from his injuries — and his alleged killer has now been charged with murder.

Grandfather Richard Williams succumbed to his injuries after he was allegedly pushed onto the tracks with another man while waiting for a train at the Lexington Avenue-63rd Station just before noon on March 8.

Alleged attacker, Honduran national Bairon Hernandez, 34, was arrested March 10 — and his charges have now been upgraded to murder following Williams’ death, court records show.

Richard Williams succumbed to his injuries after he was allegedly pushed onto the tracks with another man while waiting for a train at the Lexington Avenue-63rd Station just before noon on March 8. Obtained by NYPost

Jarring video shows suspect Bairon Hernandez (red hoodie) leering towrad the tracks after shoving the victims. Obtained by NYPost

Prosecutors had said Williams was “brain dead,” and Williams’ daughter, Debbie Williams, told The Post days after the attack her father was not likely to pull through.

The medical examiner declared his death a homicide.

John Pena, 30, was also shoved onto the tracks by Hernandez but ignored his own injuries and heroically helped pull Williams back onto the platform just moments before a train rolled into the station.

Chilling cellphone footage of the attack, apparently shot by Pena from the train tracks, shows the suspect casually strolling along the platform after pushing both men onto the subway bed.

Chilling cellphone footage of the attack, apparently shot by John Pena from the train tracks, shows the suspect casually strolling along the platform after pushing both men onto the subway bed. Obtained by NYPost

Alleged attacker, Honduran national Bairon Hernandez, 34, was arrested March 10 — and his charges have now been upgraded to murder following Williams’ death, court records show. William Miller

Hernandez, who was picked up by police on March 10, is a  “serial criminal” with a lengthy rap sheet of at least 15 charges, including aggravated assault, possession of a weapon, and domestic violence, according to the Department of Homeland Security.

He had been deported from the US four times, but kept returning to the country illegally, according to the DHS.

Hernandez is in court next on March 30.