A Royal Navy warship is helping police investigate the murder of a Cornishman.
The minesweeper is searching the seabed where the body was found
The body of 56-year-old parish councillor Peter Solheim was recovered from the sea by fishermen five miles off the Lizard on 18 June.
A post-mortem examination revealed Mr Solheim drowned, but the body also had suspicious "unexplained injuries".
HMS Walney, a Royal Navy minesweeper, is using sonar and remote-controlled submersibles to search the area of the seabed where the body was found.
Mr Solheim, from Carnkie, was last seen getting into his small white dinghy with an unidentified man at Mylor harbour, near Falmouth, on 16 June.
The man was described as white, well built and aged 50 to 55, with dark brown hair, and wearing a leaf-green jacket, which was hip or thigh length.
The following day Mr Solheim's boat, the Izzwizz, was found adrift in the harbour, with the key in the ignition.
The body was recovered five miles off The Lizard Peninsula
Police launched a murder investigation after officers deemed it was "not feasible" that Mr Solheim's body could have floated a distance of about 13 miles from Mylor to where the body was found.
Inquiries are continuing to identify the person called "Charlie" who Mr Solheim was believed to have been meeting.
Officers have not ruled out the possibility that the two men may have left from another harbour along the coast.
Detectives would also like to eliminate a green estate car, similar to that owned by Mr Solheim, which was seen by a witness parked at the Mylor Churchtown side of the crossroads near Trefusis Farm, at about 2130 BST on 18 June.
A 56-year-old local woman from the Falmouth area was arrested on 21 July in connection with the inquiry, but later released on police bail.