SEATTLE - Police are asking for the public's help in their investigation of an Aug. 23 crash involving a motorcycle in North Seattle.

A passing motorist came upon the motorcycle and its driver lying in the roadway in the 10700 block of Lake City Way NE and called 911 at about 8:40 p.m.

Officers arrived on the scene within a couple of minutes but were unable to locate anyone who actually saw the motorcyclist crash.

Investigators said the black-and-green chopper-style motorcycle was being driven by a 58-year-old man heading north on Lake City Way NE. But they could not say if he was involved in a collision with another vehicle or if he crashed on his own.

The motorcyclist is still at Harborview Medical Center on a ventilator and is not able to communicate. He sustained life-threatening injuries as a result of the crash.

Anyone who saw anything or knows anything about the circumstances surrounding this collision, is asked to call Seattle police immediately.

Anonymous tips and information also can be phoned in through Crimestoppers of Puget Sound at (206) 343-2020.