The CCTV footage shows two men walking towards the takeaway
A gun used to murder a man at a Chinese takeaway in Manchester had been used in six other shootings, police have said.
The silver revolver used to kill Halton McCollin, 20, at the China Garden in Stretford one year ago was found at a house in Parrs Wood Road last May.
Police have also released unseen CCTV footage on Youtube of masked men arriving and leaving the scene.
The footage shows two men enter the restaurant and leave shortly after and running down an alleyway.
Three shots were fired into the takeaway, causing Mr McCollin and his friends, as well as the couple who owned the restaurant, to run for cover, police said.
As Mr McCollin ran away one of the bullets hit him in his head causing injuries from which he never recovered.
Police said Halton McCollin was not involved in gangs
Greater Manchester Police believe the car that the killers used was found burnt out hours after the murder in Chorlton and hundreds of hours of CCTV footage has been examined to trace this vehicles' movements that night.
Although it is not clear who the killers are from the CCTV footage, it has been sent for enhancement for officers with specialist knowledge of Manchester's gangs to consider.
Det Supt Pete Jackson said: "Watching this CCTV footage of Halton's cold-blooded killers and knowing that they are still free makes me angry. I can only imagine what effect it has on Halton's family and friends.
"A lot can change in a year and misguided loyalties that may have existed when Halton was killed might have changed now.
"t is likely these killers bragged to people about what they did, and we need these people to have courage and come forward.
"Halton was clearly very important to his family, and had so much to live for. He was not involved in gangs at all. He had a steady job, good, decent friends, and was a promising footballer."
The Youtube film also features Halton McCollin Snr, who appeals for anyone with information to contact police.
"We need to have the people who carried out this crime removed, we have to have justice, justice for people who have suffered and died in this way.
"I can only appeal to someone having the smallest amount of information that you provide it to the correct source.
"I can draw a little bit more comfort knowing that someone else ain't going to have to go through what myself and my family have had to endure," he added.
A £20,000 reward remains on offer for information leading to the conviction of his killers.
Mr McCollin was a call centre worker and semi-professional footballer for Flixton FC.