Three thieves dug through the pockets of a dying man moments after he collapsed in the lobby of a Washington Heights apartment building, authorities said Monday.

The theft was caught on the Amsterdam Avenue building’s surveillance cameras and shows the trio rifling through the man’s pants instead of calling for help at 11:30 Saturday night, police said.

The victim, who wasn’t identified by authorities, was in his 40s and was seen walking into the lobby with the three younger men, Michael Cortes, 22, Jordano Fernandez, 18, and Angel Cabrera, 18, police said.

He was seen smoking an unknown substance shortly before he collapsed, cops said.

But instead of calling 911, the three men started digging through his pockets and stole a cellphone and bank card before running off, cops said.

The man lay on the floor for more than an hour until a passer-by called police. He was pronounced dead at Columbia Presbyterian Medical Center.

Police rounded up Cortes, Fernandez and Cabrera and charged them with grand larceny.