Police today said they remained convinced that "somebody knows exactly what happened" to Stuart Lubbock at the home of entertainer Michael Barrymore.
But Andy Bliss, Deputy Chief Constable of Essex Police, said partygoers who went to the star's then home, in Roydon, Essex, in March 2001 had "not shared this information".
He stressed that the investigation into the death of Mr Lubbock, 31, remained open.
"Essex Police is convinced that somebody knows exactly what happened to Stuart, but so far they have not shared this information with us," said Mr Bliss.
"One or more of the people at the house that night must know what went on. The passage of time makes it no easier for Stuart's family, who deserve to know what happened to him. The investigation remains open and we will pursue all leads given to us.
"It is not too late to come forward with information and we would urge anybody who has information about the events surrounding Stuart's death to contact us."
Mr Bliss said he had visited Mr Lubbock senior to apologise unreservedly for the way the initial investigation was handled.
He added: "We again offer our sincere sympathies to Stuart's friends and family for their loss."
Anyone with information about the circumstances leading to Mr Lubbock's death is asked to call Essex Police on 01245 452 207.