San Mateo police say the victim contacted police to report the assault at 9th Avenue and South El Camino Real.
Nicole Von Glahn, a detective for SMPD, said it happened 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," Von Glahn 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.
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.
Police also released a photo of the suspect's bike.
Police described the suspect as light-skinned with an average build and height with "dark outgrown or slightly curly hair."
They say he was wearing a red sweatshirt with "LIFEGUARD" on the front with dark pants.
*UPDATE* Officers contacted a female victim in her 60s, and learned she had been seriously beaten and then sexually assaulted. The suspect fled southwest on foot. To learn more, please visit https://t.co/LyJxkVR1XF. pic.twitter.com/goCfGK7Un9— San Mateo PD (@SanMateoPD) August 8, 2020
The suspect may have also been riding a silver bicycle with tape wrapped around the seat, police say.
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 email@example.com.
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.