The suspect is described as a black man in his 40s between 5 feet 10 inches and 6 feet tall and weighs about 350 pounds. The victim said the man was wearing a black tank top, blue jeans and white shoes.
Police said he's also missing an upper right tooth and has three skull tattoos across his chest.
He allegedly attacked the female custodian last week as she was cleaning a men's restroom near the running track.
If you have any information regarding this investigation, you're urged to call Cal Poly campus police at (909) 869-3070.