Campaigners who say a Leicester man was wrongly jailed for the city's so-called hot-dog murders are holding an event to highlight his case on Tuesday.
Warren Slaney has spent 15 years in jail
It coincides with the 15th birthday that Warren Slaney has spent in prison.
The Miscarriage of Justice Association, (Mojo) are releasing 15 balloons, one to mark each year of his imprisonment.
Slaney was jailed for the murders of Gary Thompson, and his employee John Weston. He was refused leave to appeal but continues to protest his innocence.
Mojo is calling for independent investigators to be appointed to look at his case.
The murders came in the summer of 1990, while the so called "hot-dog wars" reached their height, as traders fought over lucrative pitches.
It ended with the murder of Mr Thompson , known as Hot Dog King, and one of his workers.
Although an appeal into Slaney's case has been turned down, his supporters are still waiting for a review into fresh evidence, submitted a year ago.
Russ Spring from Mojo said: "We feel that the scale of the inquiry that is needed into his conviction really is beyond the scope of the Criminal Case Review Commission and they need to appoint an independent outside investigators.
"We're calling on Leicester City Council to support our call for such an investigation to be made.
"Warren's aware he's got a mountain to climb - over the years he has been frustrated by the amount of time that everything takes to move forward.
"He's a very determined man and he's very adamant and he gets more and more steadfast as the years go by."
Slaney was also convicted of robbery in the case in 1990.
The Criminal Cases Review Commission disputed the claims that they were not able to dedicate enough resources to the case.
Commission spokesman Boris Worrall said: "We've got very extensive powers to investigate, to interview witnesses, to commission reports and to look at and obtain any public documents.
"We're the last port of call for people who feel they're the victims of a miscarriage of justice - we can't cut corners here, there's nowhere else to go once you get to the commission."