A reward of £20,000 has been offered by police to help catch the killers of teenager Jessie James in Manchester.
Police say some people know the identity of Jessie's killers
Jessie, 15, was shot dead in Moss Side in September last year as he rode his bike through Broadfield Park.
Det Supt Shaun Donnellan, leading the inquiry for Greater Manchester Police, said: "I know there are people who know who killed Jessie James."
The police have offered protection for anyone who can provide information that would lead to a conviction.
Since the shooting, police have held meetings with the community, taken part in BBC One's Crimewatch reconstruction, and placed video clips on the Youtube website to encourage people to come forward.
Although there has been some success, police still need to speak to "key individuals" to try to trace Jessie's killers.
Detectives say it is hoped the £20,000 reward will act as an additional incentive for those with information to contact them.
Det Supt Donnellan added: "Some people have been reluctant to come forward and it's because they fear for themselves or their families.
"I promise I can protect you and your family, I can arrange for you to give evidence behind a screen, to have your voice distorted so that nobody in your community will ever know you gave evidence.
"Your courage could convict a killer. Think about Jessie's family. They too are victims and their suffering is dreadful. Do the right thing, tell me who took Jessie from them."