Philadelphia police have released video footage of a man accused of assaulting and robbing an elderly Temple University professor on the North Philadelphia school's campus Tuesday morning.


The robbery happened about 11:20 a.m. inside the 81-year-old professor's office at1114 Polett Walk, according to police.


The robber approached the victim while wielding a knife, demanded the man's wallet and punched him in the face. After taking the victim's wallet, he punched the victim in his face again, causing lacerations to his head and face, as well as swelling and bleeding on the brain, according to police.


The suspect is described as a black male, about 35 to 40 years old with a mustache and close-cropped beard. He was wearing a dark jacket, blue jeans and a lanyard around his neck.


Police ask anyone with information about the suspect to call the Central Detectives Division's Special Victims Unit at215-686-3047.