CHICAGO — Prosecutors in Illinois are challenging the prison sentence of Jason Van Dyke, the Chicago police officer who was convicted last year of killing Laquan McDonald and sentenced to nearly seven years in prison, a term that was criticized by many in Chicago as too lenient.

In a petition filed Monday, Attorney General Kwame Raoul and Joseph McMahon, the special prosecutor in Mr. Van Dyke’s trial, asked the Illinois Supreme Court to review whether the sentence, after a conviction of second-degree murder, was proper under the law.

“This is a question of whether the law was followed and whether a sentence was rendered on the appropriate charges,” Mr. Raoul, a Democrat who took office last month, said at a news conference on Monday, adding: “That is not a political question. That is a question of law.”

At issue is whether Mr. Van Dyke, who was also convicted of 16 counts of aggravated battery with a firearm for each of the 16 shots he fired, should be sentenced for the aggravated batteries, which could result in a significantly longer prison term. Under his current sentence, exclusively for the second-degree murder conviction, he could be released from prison in as little as three years.