PITTSBURGH -- A 20-year-old woman who was robbed at an ATM in Bloomfield was also maimed by her attacker, police said.

Pittsburgh police spokeswoman Diane Richard tells Channel 4 Action News that the victim was robbed at knifepoint on Wednesday night outside of a Citizens Bank near Liberty Avenue and Pearl Street just before 9 p.m.

Richard said the robber took $60 from the woman, then became angry when he saw a McCain bumper sticker on the victim's car. The attacker then punched and kicked the victim, before using the knife to scratch the letter "B" into her face, Richard said.

Richard said the woman refused medical treatment after the assault, which happened outside the view of the bank's surveillance cameras.

The robber is described as a dark-skinned black man, 6 feet 4 inches tall, 200 pounds with a medium build, short black hair and brown eyes. The man was wearing dark colored jeans, a black undershirt and black shoes.