'Speed racing' motorcyclist's last moments caught on camera

Video of the moments before a Melbourne motorcyclist crashed into a barrier and was thrown to his death over a bridge has been released by police.

The 32-year-old Highett man died about 10pm Sunday while racing another motorcyclist along the Bolte Bridge.

When the pair took the exit ramp, the Highett man crashed into the side barrier and was flung over the bridge.

Investigators arrested a 48-year-old Cremorne man last night and executed a search warrant at his home seizing a motorcycle which will be forensically examined.

He has since been released, pending further inquiries.

Detectives are now seeking witnesses and dash-cam footage from anyone in the area at the time.

"We are wanting to speak to anyone who was on the Tullamarine Freeway and Bolte Bridge ... and saw the two motorcycles riding dangerously," Detective Inspector Stuart McGregor this morning.