WA police are investigating potential links between human remains inside a burnt-out vehicle, another vehicle that was submerged at a nearby jetty, and a man behaving "erratically" who was found drifting at sea.
The alarm was first raised of a vehicle ablaze in the Cervantes area north of Perth about 12.30am on Tuesday.
Investigations revealed what police believe to be human remains inside the vehicle.
Later in the morning, police were advised of another vehicle submerged in water off the beach south of the Cervantes Jetty.
A vessel was then spotted drifting out to sea with a man aboard acting "erratically", who then jumped into the water.
The man was rescued by a nearby fishing crew and later taken into custody by police where he is receiving medical treatment.
"Inquiries are continuing in an attempt to determine all the circumstances surrounding both incidents, and whether they are linked," WA Police said in a statement.
One of the members of the fishing crew told ABC News the man was naked and "played dead" in the water before being rescued.
"Nothing the guy said made any sense," they said.
The submerged vehicle was recovered from the water and nothing suspicious was located inside, police said.
Police are appealing for any information or dashcam footage travelling in both directions along Indian Ocean Drive from 9pm on Monday to 12.30am on Tuesday.
