The search for the small plane that plunged into the ocean off Victoria's surf coast, killing four, has uncovered maintenance records but still no sign of a fourth body or the aircraft.
Police say maintenance records from the plane were handed in by a member of the public who found them washed ashore on the beach over the weekend.
The documents may help solve Friday's fatal crash when the Piper Cherokee aircraft went into the water amid poor weather off Point Lonsdale on a trip from Melbourne's Moorabbin Airport.
Names of the victims have not been released but Daniel Flinn, 55, Donald Hateley, 68, and Ian Chamberlain and his partner Dianne Bradley, both aged in their 60s, are believed to have died in the crash.
The bodies of three of them were recovered from the wreckage on Friday.
The three men were all licensed private pilots, but it's not clear who was flying the plane.
Police say the hunt for the fuselage, where the fourth body is believed to be trapped, is proving hard, even with sonar technology.
Water police and search and rescue teams will spend Tuesday scanning underwater using remote-operated vehicles as the search enters its fifth day, a Victoria Police spokeswoman said.
A surface search is also continuing and members of the public are requested not to touch anything they might find on the shore that looks like it could come from the plane, but to call police immediately.
The Australian Transport Safety Bureau is investigating the crash.
A spokesman said on Tuesday ATSB investigators were waiting for Victoria Police to find the wreckage and remove it from the water before they can fully investigate.
