In September 2002, police found a burning Mercedes-Benz SUV on a Studio City street.
Inside were the bodies of 35-year-old Michael Tardio and 31-year-old Christopher Monson.
Both had been shot.
A reward in the case stands at $75,000.
Police said they believe the two were killed as they tried to sell jewelry belonging to Tardio's girlfriend, featured in Playboy Magazine.
Anyone with information on the case is urged to call 1 (877) LAPD-24-7 or (877) 527-3247.