Vancouver police are issuing a warning after a series of sexual assaults on or near the seawall, and hoping the public can help identify their suspect.

In all four incidents, women ranging in ages from their late 20s to their late 30s were groped, and the suspect fled on a bicycle.

Police say three of the assaults occurred Aug. 11 between 9 p.m and 9:45 p.m. on the seawall in the Yaletown and Granville Island areas. The women were all walking on the seawall, and the attacker rode by, groping them without stopping.

Police say one victim was knocked to the ground by the man.

A fourth woman was sexually assaulted Aug. 13 at 12:30 a.m. near Cornwall Avenue and Cypress Street.

Police say they believe the attacker was the same man in all four instances.

The man is described as being in his 20s to early 30s, five feet nine inches tall, with a slim build. He has darker skin with black hair in a short buzz-cut and was riding a dark-coloured bicycle.

Police believe there was at least one other woman who was sexually assaulted but has yet to come forward.

Anyone with information is asked to call Vancouver police at 604-717-0603 or Crime Stoppers at 1-800-222-8477.