Mercer was found guilty of murder after a nine-week trial
The teenage killer of schoolboy Rhys Jones has lodged an appeal against his conviction and sentence.
Sean Mercer, 18, of Good Shepherd Close, Croxteth, Liverpool, was convicted of the 11-year-old's murder at Liverpool Crown Court last month.
He was sentenced to life in prison after the nine-week trial, and ordered to serve a minimum tariff of 22 years.
The Criminal Appeal Office at the Royal Courts of Justice in London confirmed papers for an appeal had been received.
The appeal arguments have not yet been revealed but will be considered by a single judge, who will decide whether they are strong enough to go to a full appeal hearing before three senior judges.
Mercer was 16 when he shot Rhys outside the Fir Tree pub in August 2007, as the schoolboy walked back to his home from football practice.
He was shooting at members of the rival Norris Green gang when one of the bullets hit Rhys in the neck.
Rhys bled to death in his mother Melanie's arms just minutes away from his home.
Five fellow gang members were convicted unanimously of assisting an offender after they helped Mercer evade the police for months.
A sixth was convicted of four related charges.
At the end of the trial, judge Mr Justice Irwin branded Mercer a "coward" and described the gang members as "selfish and shallow criminals".
Mercer had 28 days from his conviction on 16 December to lodge his appeal.
A spokeswoman for the Crown Prosecution Service said: "We will be resisting this appeal and we expect it to be listed for a hearing in due course."