The 17-year-old girl was in the park on Santa Rosa Avenue around 8:30 p.m. when she asked a man sitting near her if she could use his phone to call someone for a ride home, Sgt. David Linscomb said.
The man gave her his phone, but then grabbed her and dragged her under a tree, where he removed her clothing and raped her, Linscomb said.
The girl was able to get away when a group of young men called to the suspect and asked him what he was doing, causing him to get off her.
The victim left the park and walked to the Roxy Theater, where she called for a ride, Linscomb said.
The attacker is described as a white male, possibly in his 20s, between 5 feet 9 inches and 6 feet tall, wearing checkered shorts with a gray belt and a chain hanging from them.
Anyone who may have witnessed the attack or who has information on the identity of the suspect is asked to call police Detective Jeneane Kucker at (707) 543-3595.