12/12/2010 12:28 pm ET | Updated May 25, 2011

Drew Peterson's Son Stephen Should Be Fired, Says Oak Brook Police Chief

Oak Brook Police Chief Thomas Sheahan testified last night that Stephen Peterson, son of murder suspect Drew Peterson, should be fired from the police force.

Sheahan's remarks come during an investigation into inappropriate behavior on the part of the younger Peterson, who has admitted to withholding evidence in Drew's case from law enforcement.

Stephen testified in August that he had been approached by his father in October 2007, just days after his step-mother Stacy Peterson disappeared. Drew gave his son three guns, and three checks totaling $236,800, asking him to keep the guns safe from investigators and use the money to take care of his family, according to Stephen's testimony.

After Stephen took the stand and owning up to these facts, the Oak Brook Police Department, of which he is an officer, placed him on paid leave pending a further investigation.

The police board has since been looking into the matter, and it was before that body that Chief Sheahan made his remarks.

More from the Chicago Tribune:

Sheahan testified Thursday night that by not telling state police immediately after his father gave him the guns and cash, Peterson obstructed their investigation, because either of those items could have been crucial to investigators.

"This should have raised a flag with Officer Peterson," Sheahan said. He later added: "In my own opinion, if it was a toaster, it's a piece of evidence and he should have cooperated with state police."

The August suspension wasn't the first in Officer Peterson's career. He had, in fact, been suspended previously on a charge related to his father's trial: he drove a squad car to an early hearing of Drew's, and testified in full police uniform, a blatant violation of police policies.

Stephen was suspended three other previous times in his six-year career, including once for using his patrol car computer to send inappropriate messages about a "female civilian," the Trib reports.