Human remains have been found inside a car at the bottom of a dam in Queensland's Mary Valley and police have said the car belongs to missing Tasmanian man Stuart Gatehouse.
Police removed the vehicle from Borumba Dam near Imbil on Thursday after a member of the public, using a depth sounder, detected a large object near the boat ramp.
The homicide squad is assisting detectives after skeletal remains were found inside the car.
The red Holden belongs to a Tasmanian man who disappeared in April 2004, police said on Friday.
Stuart Gatehouse was 45 years old when he disappeared near Kenilworth.
Thursday would have been his 58th birthday.
"However at this stage it's far too early in the investigation to be making any speculation as to who the deceased person that is located in that vehicle, the skeletal remains, who that person may be," said Acting Detective Superintendent David Drinnen on Friday.
"As you would be aware, there's a number of forensic examinations that we'll have to undertake, until such time as a formal identification can be made in relation to the skeletal remains."
Police said at this stage the cause of death is not known.
Acting Detective Superintendent David Drinnen said, "We have not been able to establish what has transpired in relation to the vehicle that has been located submerged in the dam.
"As with most of these matters, you know, it's important that we undertake a thorough and methodical investigation so we can make a determination as to what has occurred.
"At this point it'll be treated as suspicious until we know otherwise."
Sunshine Coast CIB detectives are being assisted by the State Homicide Squad with their investigation.
Anyone with information is urged to contact Policelink on 131444 or Crime Stoppers on 1800 333 000.