Detectives investigating the murder of a man whose body was found in an oil drum in the River Clyde yesterday said they were focusing their inquiry on how the barrel entered the water.

Council workers found the partially decomposed body of William (Billy) Bates during a routine cleaning and dredging operation near the Erskine Bridge in West Dunbartonshire last Thursday.

Police launched a murder inquiry saying he had been the victim of a "sustained attack" and suffered "horrific injuries". They said his body could have been in the water for between three and 14 days.

It was later reported that Mr Bates, 43, from Possilpark, Glasgow, had been the prime suspect in the killing of barman Thomas Cameron who was shot in the car park of the Auchinairn Tavern in Bishopbriggs, near Glasgow, on June 28.

Detectives hope tracking the movements of the oil drum could provide vital clues which could help solve the murder.

Police yesterday said they had information that the drum may have been in the area where it was found last Tuesday, two days before the body was found.

Detective Superintendent John Riggans, who is leading the inquiry, said: "We are currently trying to establish exactly where and when the oil drum was placed in the water.

"I believe the drum would have entered the water near to where it was recovered under the Erskine Bridge, and it could have been put into the river from either the Erskine or Bowling side of the river.

"If the drum was taken to the river from elsewhere then a large vehicle must have been used in its transportation.

"I would urge anyone who frequents these areas, particularly those using pleasure or commercial craft on the water, or possibly dog walkers or joggers, to think carefully if they saw any suspicious activity in the days or nights before Tuesday, July 24, 2007."

Mr Riggans refused to comment on speculation that Mr Bates's death was linked to Mr Cameron.

He said Mr Bates had not been seen by his family and friends for several weeks before the discovery of his body.