A DuPage County judge on Monday upheld the decision of the Oak Brook Police Department to fire Stephen Peterson in 2011.
Oak Brook village officials said Peterson "delivered contradictory testimony, failed to disclose information and demonstrated poor judgment" during an Illinois State Police investigation into the disappearance of Stacy Peterson, Drew Peterson's fourth wife, according to the Chicago Tribune.
Officials also said Stephen Peterson hid three of his father's firearms while the Illinois State Police executed a search warrant on the elder Peterson's house in November 2007.
Stephen Peterson has 30 days to appeal the decision. He filed a $10 million federal lawsuit against the Oak Brook Police Department over his termination in 2012, according to the Chicago Tribune.