San Mateo police say the victim contacted police to report the assault at 9th Avenue and South El Camino Real around 10:45 p.m.
"She was beaten and raped and the suspect fled the scene immediately after. We believe he was near the bus stop when she was assaulted," Nicole Von Glahn, a detective for SMPD, said.
Police say the suspect left the scene on foot and a search is now underway.
The suspect is described as a white or Hispanic man in his late teens or early 20s and believe he is homeless.
San Mateo police released surveillance footage to ABC7 Saturday afternoon showing a man they believe to be the perpetrator in the assault.
The footage shows a man walking on a street, though it's unclear where or when the video was taken.
On Sunday, police released a photo showing the victim's face and describe the suspect as light-skinned with an average build and height with "dark outgrown or slightly curly hair."
Detectives say they have now found the red sweater and bicycle they believe the suspect was wearing and riding.
Police are asking residents and business owners to check their security cameras for video matching the suspect.
"After he discarded his red sweatshirt he was wearing a white t-shirt and he had a very specific satchel like bag going across his chest," Von Glahn said.
Von Glahn said it was a very uncommon event for the area, residents nearby agree.
"It's a very low crime neighborhood. I mean the only thing that happens around here is people going through your car," San Mateo resident Helen O'Day said.
Stephane Gourguechon would describe the area as extremely safe, which is what makes it surprising.
"I've lived here for four years now, never heard anything remotely like it," Gourguechon said.
The police department believes the suspect visited businesses in San Mateo.
Those with information on the assault or suspect should contact San Mateo Detective Sergeant Lee Violett at (650) 522-7662 or by email at firstname.lastname@example.org.
Anonymous tips can be submitted to police here or by phone at (650) 522-7676.
Police are requesting any security footage from Wednesday between 10 p.m. and 11:30 p.m.