Brodsky identified the gun as an AR-15 semiautomatic assault rifle. He said Peterson, who was a Bolingbrook police officer, was exempt from the length provision. He also said Peterson, who is now retired, was still serving on the force when the gun was seized by police.
Peterson's wife, Stacy, went missing in October 2007. Her disappearance led officials to reopen the death investigation of Peterson's third ex-wife, Kathleen Savio in 2004. Her body was exhumed and Savio's death has since been labeled a homicide.
Peterson was named a suspect in Stacy's disappearance, but has not been charged in that case or the Savio case. He maintains his innocence in both cases.
The gun in question is one of 11 seized during a November 2007 search of Peterson's Bolingbrook home. Those guns were expected to be returned to Peterson's son on Thursday. Now, Brodsky said a judge is expected to rule immediately on the existing gun case.
"For some reason I can't fathom, state police seem fixated or obsessed with making sure Drew or his family can't get these weapons back," said Brodsky. He also said "Drew has never fired a gun in anger."
Peterson turned himself in after a warrant was issued for his arrest. His bond was set at $75,000, according to his attorney. Peterson's grown son reportedly posted 10 percent of his bond Wednesday afternoon. Peterson made no comment to reporters at the scene.
"Drew will be home by dinner," said Brodsky. "If they thought this was a tactic, it won't work." Peterson did arrive back home at 4 p.m.