BOLINGBROOK, Ill. - Months after naming a former suburban Illinois police sergeant as a suspect in his wife's disappearance, authorities issued a warrant yesterday for his arrest on an unrelated weapons charge, officials said.

Drew Peterson turned himself in shortly after the warrant was issued.

The gun, a semiautomatic assault rifle, was one of 11 seized during a search of Peterson's home Nov. 1, shortly after Stacy Peterson disappeared in late October, said his attorney, Joel Brodsky. He said police claim the rifle barrel was too short under Illinois law.

Brodsky said Peterson was still a police officer when the weapon was seized and officers are exempt from the length provision of the law. Peterson retired from the force after his wife's disappearance.

Police also are investigating the death of his third wife, Kathleen Savio. She was found dead in a bathtub in 2004. Her death was initially ruled an accident.

After Stacy Peterson disappeared, Savio's body was exhumed and an autopsy determined she was the victim of a homicide.

The investigation into Stacy Peterson's disappearance has drawn worldwide media attention. Authorities have said they believe she is dead, and extensive searches have been conducted in forests, marshes, lakes and other areas in suburban Chicago.

The felony gun charge, unlawful use of a weapon, carries a penalty of up to five years in prison. Peterson was expected to post 10 percent of a $75,000 bond to be released, authorities said.

Peterson has been trying for months to convince a judge to order the Illinois State Police to return the seized weapons. The judge already ordered police to return Peterson's vehicles and other belongings. *