The elderly Lehman College professor who was beaten inside an Upper West Side bank vestibule has died of his injuries, cops said on Friday.

Young Kun Kim, 87, died Thursday afternoon as a result of the attack, police said.

The suspect approached the victim from behind around 4:30 p.m. Sunday as he used an ATM inside a CitiBank on Broadway near the corner of 101st Street, according to video posted to Twitter by the NYPD’s 24th Precinct.

He punched Kim in the head, stole cash and fled.

The professor was rushed to Mount Sinai Hospital, where he was listed in “extremely critical condition” and placed on life support.

Matthew Lee, 50, was arrested Wednesday night and charged with robbery and assault, cops said. His charges have not yet been upgraded.

Lee has one prior arrest, for an assault in 1984, police said.

“Dear God,” tweeted Lehman College Associate Dean Christopher Malone on Tuesday. “This is Lehman professor Young Kun Kim. His son tells me is in a coma and in palliative care. Our hearts weep. He is the most peaceful person on this planet.”