A million-dollar reward is on offer for the execution-style killers of mobster Willie Thompson, gunned down at the height of the gangland wars that rocked the Melbourne underworld more than 14 years ago.

Thompson was murdered while alone in his vehicle on Waverley Road in East Malvern at about 9.30pm on July 21, 2003, becoming what police say was the twenty-second casualty in the wave of bloody terror that eventual left 36 people dead.

Drug kingpin Carl Williams orchestrated a wave of gangland hits.  ABC

The 39-year-old Thompson had just left a nearby martial arts gym when he was shot several times by two men who pulled up beside his his two-seat sports car.

At the time of his murder, Thompson was known to police and had a number of connections to a range of gangland figures including Nick Radev, rubbed out in a gangland hit two months earlier, and drug czar Carl Williams, later beaten to death in prison.

Thompson, a sometime nightclub bouncer who listed his occupation as “lollipop salesman”, was known to be involved in drug trafficking, with particular links to Western Australia.

In announcing the reward, officer in charge of the Purana Taskforce, Detective Inspector Tracie McDonald, described Thompson as the “forgotten gangster”.

“Thompson’s death came during a time when a number of gangland figures were being murdered, however, it never received a lot of public or media attention,” she said.

Willie Thompson: “Lollipop salesman” with a sideline in drugs. VicPol

In 2004 police received anonymous information regarding the murder of Thompson and detectives are particularly keen for that person to contact them again.

“We know there are still people out there who know exactly what happened to Willie Thompson and why, and we’re appealing for those people to come forward,” Det Insp McDonald said.

“Fourteen years is a long time and obviously circumstances can change, so people who did not feel comfortable speaking to police at the time may now be in a position to do so.

“We’re confident that this murder is solvable – all we need is the right information from the right people.”

-with AAP