Another woman was assaulted by a passing cyclist on a river valley trail, say Edmonton police.

The woman reported she was riding her bike at 6 p.m. Sunday when she was assaulted in the Queen Elizabeth Park area.

The woman, who was not hurt, did not report the attack until a few days after the incident, said Det. Lisa Mah.

"Although we are glad the complainant reported this incident, it is crucial to report a crime to police immediately so we can dispatch the necessary resources that could help apprehend the suspect,” she said.

Police believe the attack may be linked to other assaults that have taken place on bike trails this year in the Gold Bar, McNally, Dawson and Muttart Conservatory areas.

In all of the cases, the suspect is riding a bicycle on the bike paths and grabs the victims from behind.

The victims ranged in age from 30s to late 50s, said Mah.

Police are investigating six similar incidents since September 2011, but believe there are more victims who have not come forward.

"I think with a lot of people...say, 'I wasn't physically hurt, I didn't fall off my bike, I'm just going to let it go.'"

The assaults happen very quickly, so descriptions vary, said Mah.

The suspect is described as a Caucasian male with an average build, 5’10” to 6’0” tall, 30 to 50 years of age and has long grey hair tied in a pony tail.

He was seen riding a blue bicycle and may be wearing a bicycle helmet or hat.