A teenage gunman has been jailed for life after being found guilty of the murder of 11-year-old Rhys Jones.

Gang member Sean Mercer, 18, was convicted at Liverpool Crown Court of blasting three bullets across a pub car park in Croxteth, Liverpool, after targeting rivals who had strayed on to his "turf". He will serve a minimum of 22 years.

Innocent schoolboy Rhys was caught in the line of fire and shot in the neck. He died in his mother's arms.

The jury of seven women and five men convicted Mercer of murder unanimously on Monday but the verdict could not be reported until now.

What the jurors did not know was that just two months before he shot Rhys, Mercer was involved in a chilling rehearsal of the killing. Waving a gun, he rode a motorcycle past members of the public on rival gang territory.

Jurors were also unaware that Mercer was given a three-year Asbo for terrorising security guards at a sports centre just weeks after shooting Rhys.

Fellow gang members James Yates, 20, Nathan Quinn, 18, both of Croxteth; Gary Kays, 26, and Melvin Coy, 25, both of West Derby, and Boy M, 16, who cannot be named, were convicted unanimously of assisting an offender. Dean Kelly, 17, was also convicted of four related charges.

Kays and Coy were both jailed for seven years. The rest of the gang will be sentenced at a later date.

The judge, Mr Justice Irwin, told Rhys's killer: "You were caught up in gang activity at a young age and it is clear you gloried in it. Rhys Jones died because of your brutality and because you are a coward."

Mercer, of Good Shepherd Close, Croxteth, was a leading member of the Croxteth Crew gang, which terrorised the local community and was involved in a bloody feud with the Strand Gang, based on the neighbouring Norris Green estate.

Mercer had an "intense hatred" of Strand rival Wayne Brady. When Coy and Kays told him that Brady and two others had been seen cycling near the Fir Tree Pub on Croxteth Crew territory, Mercer armed himself and prepared to attack.

Dressed in a black hoodie and tracksuit, Mercer fired three shots at Brady's friends with Yates's Smith & Wesson .455 revolver.

Rhys, distracted by the sound of the first bullet hitting a shipping container in the car park, turned toward the gunman and was struck in the neck by the second shot. Mercer then adjusted his position to aim one final round at his rivals.

Mercer then cycled to the home of Boy M and called on fellow gang members to help him avoid the law. With Yates, Quinn and Kays, he was driven by Coy to a lock-up garage on an industrial estate where his clothes were burned and his body washed down with petrol.

Mercer gave the murder weapon to 17-year-old Boy X, who who hid it in a dog kennel. Kelly later stashed it in his loft along with a second gun and ammunition, where police found it later.

A crucial breakthrough in the police investigation came three months later when Boy X accepted immunity from prosecution in exchange for giving evidence against the gang.

© Independent Television News Limited 2009. All rights reserved.