Mark Searle, 36, from St Leonards-on-Sea, was found guilty of murder, conspiracy to kidnap and perverting the course of justice at Lewes Crown Court.
His victim, Jason Martin-Smith, 28, of Camberley in Surrey, was abducted in Hastings, East Sussex, in August 2001.
Searle, of Chambers Road, will serve a minimum of 29 years.
The murder is believed to be linked to the killing of 27-year-old Jimmy Millen who was shot outside his Hastings home by two men on a motorbike in 2001.
Mr Martin-Smith was an acquaintance of Mr Millen.
Det Ch Insp Paul Rymarz said it was during the investigation into Mr Millen's murder that information relating to the murder of Mr Martin-Smith came to light.
His body was never found, but officers established he was dismembered in a lock-up.
After the hearing, Mr Rymarz said: "Our thoughts are with his family who have waited a long time for this result."
Another defendant, Steve McNicol, 42, of Whitefriars Road in Hastings, was earlier convicted of conspiracy to kidnap and jailed for four-and-a-half years.
He was also accused of murder but the charge was discontinued by the Crown Prosecution Service at the start of the trial.
A man has been jailed for life over the murder of a man 14 years ago whose body has never been found.