A man suspected of rape in San Francisco's Hayes Valley this morning was already acquainted with the victim, according to police.

Officers responded to the 1800 block of Market Street on the report of a suspected rape at about 3:35 a.m., according to police.

They found a victim who said the alleged rapist was about 22 years old with a light complexion, weighing about 160 pounds and nearly 5 feet 10 inches tall.

The suspect was wearing a gray button down shirt with a blue hat at the time of the rape, police said.

He also has a tree tattoo on his left forearm, police said.

An investigation revealed the victim and suspect knew each other, and that the suspect does not present a threat to the public, Sgt. Mike Andraychak said.

The victim identified her attacker and police are still on the lookout, Andraychak said.

Anyone with information about the case is encouraged to call the San Francisco Police Department's anonymous tip line at (415) 552-4901.

Due to confidentiality and privacy concerns, San Francisco police aren't releasing any details about the victim.