MILLBRAE, Calif. (KRON) — A woman out for an evening walk was the victim of a sexual assault Sunday at around 7:30 p.m. It happened on a popular neighborhood trail on the Peninsula. The police are asking for the public’s help to identify the person responsible.

“It’s very said. I hope they find the person responsible for this incident,” said Millbrae resident Rosemary Ferdenzes.

Investigators with the San Mateo County Sheriff’s Office say a 28-year-old female was walking alone along the Spur Trail when she was approached from behind and groped below the waist. The man then rode off on a black mountain bike. He matched the description of a person in this photo released by police.

People who use the trail in this quiet neighborhood say until now they considered it safe.

“Very safe,” said Ferdenzes.

“It’s always been very safe,” agreed resident Daniel Lawson.

“Absolutely, because there’s so many people here, and there’s a lot of traffic all of the time,” added Rosemarie Lashkoff.

A woman being the victim of a sexual assault has rattled the nerves of some folks here on the trail.

“I would probably avoid an area like this around that time just because it’s usually darker,” said Millbrae resident Levon Pelt.

There are lights up above on the residential side of Millbrae Avenue. However, trail users say those lights are too far away to illuminate the walking path at night.

“It’s not illuminated, but that’s part of the trail,” said Lawson. “The appeal of the trail is that it’s not illuminated at night.”

“Illumination would be a great idea, especially since this has occurred, yeah!” said Ferdenzes.

Investigators say after the assault, a man matching the description of a person seen in photos released by police was last seen riding a black mountain bike toward South Ashton Avenue. If you think you recognize the person, you’re asked to contact the San Mateo County Sheriff’s Office.