CHICAGO (Reuters) - Illinois Attorney General Kwame Raoul and a prosecutor on Monday challenged the sentence of former Chicago police officer Jason Van Dyke for the murder of a black teenager, questioning whether the judge who imposed it followed the law due to his failure to account for other convictions.

FILE PHOTO: Chicago police Officer Jason Van Dyke watches the prosecution's closing statements during his trial for the shooting death of Laquan McDonald at the Leighton Criminal Court Building in Chicago, Illinois, U.S., October 4, 2018. Antonio Perez/Chicago Tribune/Pool via REUTERS/File Photo

Van Dyke, 40, who is white, was sentenced last month to nearly seven years in prison for second-degree murder in the shooting death of Laquan McDonald in 2014 in a case that highlighted racial tensions in America’s third-largest city.

Activists and prosecutors had wanted a longer sentence. Van Dyke could have received up to 20 years in prison for second-degree murder and up to 30 years for each of 16 counts of aggravated battery - one count for each shot he fired at the 17-year-old McDonald, who was carrying a knife.

Cook County Circuit Court Judge Vincent Gaughan did not sentence Van Dyke for the aggravated battery convictions, explaining that second-degree murder was the more serious crime. Van Dyke is appealing the conviction.

Raoul, who took office last month, and Kane County State’s Attorney Joseph McMahon, the special prosecutor in the case, filed a petition on Monday asking the Illinois Supreme Court to review the sentence.

They argued that aggravated battery is a more serious offense than second-degree murder under Illinois law and requested the supreme court direct Gaughan to vacate his sentence. They also asked for a sentence on each of the 16 counts of aggravated battery and to determine which of those involved “severe bodily injury” warranting consecutive sentences.

“This is a question of the law. And it is in the interest of justice that the law be followed no matter who the defendant and no matter who the victim is in a particular case,” Raoul told reporters.

Van Dyke’s attorneys Darren O’Brien and Jennifer Blagg said in a statement the petition was politically motivated and “could result in grossly excessive, unjust sentences for defendants that follow in the wake of this request.”

The guilty verdict issued by a jury in October marked the first time an on-duty Chicago police officer was convicted for the killing of a black person.

The release of a police dashboard camera video showing McDonald being repeatedly shot - compelled by a lawsuit more than a year after the Oct. 20, 2014, shooting - ignited protests.

The ensuing firestorm over the case prompted the dismissal of the city’s police superintendent and calls for Chicago Mayor Rahm Emanuel to resign. Emanuel is not seeking a third term in this month’s mayoral election.

The video was shown repeatedly during Van Dyke’s three-week trial. Jurors said they faulted Van Dyke for escalating the incident.

A federal judge on Jan. 31 approved court-appointed oversight of the Chicago Police Department to address a 2017 U.S. Justice Department finding of excessive force and racial bias by officers.