Joseph Harrington, who was jailed for life after being convicted of murdering Sylvia King, who was burnt alive in her car on April 4, 1993 at Kunċizzjoni, limits of Rabat, died at Mater Dei Hospital where he was receiving treatment.
Mr Harrington was convicted of the murder in 1997 together with Tommy Baldacchino, who in 2003 was discovered dead of a suspected heroin overdose at his flat in Bugibba.
Mr Baldacchino had given the police a detailed account of the murder and said he had wanted to stop Mr Harrington but was afraid he would also be killed.
Mr Baldacchino was released from prison in 2002.