The attorney general is reviewing the seven-year jail term imposed on the teenager who supplied the gun that was used to kill schoolboy Rhys Jones.
James Yates was described by the judge at Liverpool Crown Court as a "willing assistant" to murderer Sean Mercer, 18.
Yates, 20, of Croxteth, provided the Smith and Wesson handgun used to kill Rhys and helped with its disposal.
The attorney general can refer the case to the Court of Appeal if she believes the sentence is "unduly lenient".
An unduly lenient sentence is one that is significantly below what a judge could reasonably have given at the conclusion of the trial.
If the case is referred to the Court of Appeal, three judges will decide whether the sentence should be changed.
Speaking after Yates was sentenced last month, Rhys's parents Stephen and Melanie Jones said: "We feel seven years is a disgrace."
The couple added: "In our minds he is the one who provided the gun that killed our son and he deserved a longer sentence."
The decision to look at the Yates case came after representations from the Crown Prosecution Service (CPS), Attorney General Baroness Scotland's office told BBC News
Rhys, 11, died in his mother's arms after he was shot in the car park of the Fir Tree Pub
, Croxteth Park, on 22 August 2007.
Mercer was jailed for life for his murder.
Yates was one of six members of the Croxteth Crew gang who helped him evade police.
Yates, of Dodman Road, was found guilty of assisting an offender and possessing a banned firearm. THE BBC