Peterson surrendered to state police Wednesday on a charge of felony unlawful use of a weapon, which by law was too short, By mid-afternoon. he was on his way back to his suburban Chicago home after posting 10 percent of a $75,000 bond, the Chicago Tribune said.

The guns, 11 in all, had been seized in a police search on his home. One assault rifle was deemed illegal because of the shortness of its barrel, a charge carrying a potential penalty of up to 5 years in prison. Peterson's attorney accused authorities of trying to rattle his client.

Peterson, 54, a former Bollingbrook police sergeant, has been named a suspect in the Oct. 28 disappearance of his fourth wife, Stacy, who was 23 at the time. He has not been charged.

Authorities are also conducting a murder investigation into the 2004 drowning of his previous wife, Kathleen Savio. Peterson has not been charged in that case either and insists he has done nothing wrong.