The Oak Brook Police Department suspended former police Sgt. Drew Peterson's son Wednesday for wearing his police uniform and driving his squad car to grand jury appearances.

Stephen Peterson received an eight-day suspension after a commission hearing, My FOX Chicago reported. Peterson appeared before the grand jury in November 2007 and December 2007.

Peterson said no supervisor told him he couldn't wear his uniform or drive the squad car until after his appearances.

"I was never told I couldn't take the squad car or wear my uniform," Peterson said at the commission hearing.

Peterson's Oak Brook police chief filed charges in February, accusing him of violating policy.

Peterson is a suspect in his wife's Oct. 28 disappearance. Stacy Peterson was reported missing after she failed to show up at a friend's house. Peterson denies any wrongdoing and has not been charged.

The grand jury is investigating Stacy's disappearance and the 2004 death of Peterson's third ex-wife, Kathleen Savior.

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The Associated Press contributed to this report.