Sean Mercer's name was in the frame for police early in the inquiry
The shooting of Rhys Jones prompted the beginning of a long and painstaking investigation to find his killer.
Several names were in the frame from day one - including Sean Mercer's.
But, as investigating officer Det Supt Dave Kelly observed, a name is one thing, evidence is another.
It took officers using techniques honed in counter-terror operations eight-and-a-half months to amass enough evidence to bring charges.
In the days following the killing in August 2007, a team of 60 officers and four firearms recovery dogs scoured the scene outside the Fir Tree pub in Croxteth, Liverpool, carrying out what they called the most arduous fingertip search they had ever conducted.
The examination was so comprehensive that 120 sq m of hedgerow and undergrowth was cut down and scrutinised, with each branch or shrub collected in tarpaulin for fear of a morsel of evidence falling through the net.
Merseyside Police pulled together to get justice for Rhys
Det Supt Dave Kelly
A second area of scrubland was also searched, by which time officers had put in 800 hours and worn through 40 pairs of protective boots in their hunt for clues.
After eight more areas were explored - some with the help of underwater search teams - several guns and even an ammunition factory had been found.
A total of 32 properties were searched, with investigators using bugging devices in some cases to record conversations held in the days following the murder.
One of those devices, in the home of Boy M, picked up a conversation between the 16-year-old and Mercer, Yates and Quinn where they were heard pressurising Boy M's grandmother into covering their tracks.
The evidence gathered from the listening devices was one of several key breakthroughs in the case.
Det Supt Dave Kelly on a 'moving' case
Another of those was the arrest of a youth known only as Boy X - a teenager whose evidence was so useful to the police that the almost unprecedented decision was taken to grant him immunity from prosecution in return for his side of the story.
Faced with his evidence, the Crown Prosecution Service (CPS) had to decide whether it was in the greater public interest to prosecute Boy X, or to get a conviction for murder suspect Sean Mercer.
After referring the decision to the highest level, it was decided to proceed with granting Boy X immunity under the Serious Organised Crime and Police Act 2005.
This was only the second time the act has been used - the first being the case of the Securitas cash depot robbery in Kent in 2006, where charges against make-up artist Michelle Hogg were dropped in return for her evidence.
In this case, the CPS said Boy X was a youth who had never been in trouble with the police before and he was granted anonymity and immunity from prosecution.
Several guns and an ammunition factory were found by police
Days later, a major police operation involving a team of 200 officers carried out raids on 11 homes and made 13 arrests.
Mercer was then charged with murder and six others were charged with helping him cover up his crimes.
Boy X went on to be the prosecution's "star" witness.
Det Supt Kelly said that throughout the case, getting justice for an innocent child was their number one priority.
"This investigation has been the most challenging and moving that I have ever had to deal with," he said.
"Merseyside Police pulled together to get justice for Rhys."
He added that the next step was dealing with the gang culture in the Croxteth and neighbouring Norris Green areas.
"It's important that we tackle this head-on. Dismantle these gangs.
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