CHICAGO (CBS) – Police are looking for a man who robbed and punched a Northwestern University staff member early Tuesday in the Streeterville neighborhood.

The man came up to the female staff member in the 300 block of East Ontario Street and demanded money. The woman turned over a credit card, according to a release from Northwestern University police.

The man then demanded the woman’s wallet, and she said she didn’t have one. The man then punched the woman two or three times and fled east on Ontario Street.

The woman walked a few blocks to Northwestern Memorial Hospital, where she was treated for her injuries and released. She also reported the robbery to Chicago Police.

The suspect is described as an African-American man between the ages of 30 and 40, standing 5 feet 10 inches tall and weighing 150 pounds, with brown eyes, black hair and a dark brown complexion. He was wearing a black hooded sweatshirt under a black coat, Northwestern police said.

The scene of the crime is close to the Chicago Campus of Northwestern, which includes the medical and law schools. But the block where it happened is dominated by a parking garage and a long empty lot where the old CBS Building once stood.

Northwestern University police advise anyone who witnesses suspicious activities or people to call them with a via a blue-light emergency phone, or call Chicago Police by dialing 911.

The Sun-Times Media Wire contributed to this report.