Police are seeking information on a possible case of road rage that left a 35-year-old Forrestfield man seriously injured earlier this month.
At about 1.50pm on June 5 the man was on a motorcycle traveling on Roe Highway, Beckenham near the Albany Highway overpass.
Police believe a road rage incident may have occurred involving another vehicle tailgating the motorcyclist.
The rider moved to the side and it appeared the vehicle then cut him off, causing him to fall.
There was no contact between the motorcycle and the other vehicle.
The motorcycle slid into a bridge support pylon, and the rider came to rest just 5m short of the same pylon.
The vehicle involved has been described as an older model four door sedan, similar to a Hyundai sedan.
The vehicle is believed to be a faded red colour, possibly with a blue panel on it.
Anyone with information about this crash can call Crime Stoppers on 1800 333 000.