Vancouver police are asking for help locating the suspect in an attempted sexual assault on a 19-year-old woman on Tuesday night.

The victim had just gotten off a bus in the 3500-block of SE Marine Drive and was beginning her walk home, when she noticed a man following her.

As she entered a trail around 11:15 p.m., she was grabbed from behind. Police say the man then grabbed at her clothing and tried to force her further into the trail.

A passerby heard the noise and intervened, scaring the suspect, who ran to the east along Marine Drive.

Police are now looking for a white man in his 30s, estimated to be 6-2 tall and thin, with short, light-coloured hair. He was wearing frameless glasses with a long-sleeved blue plaid shirt and jeans.