SPOKANE, Wash. -

Spokane County Sheriff Ozzie Knezovich has fired one of his deputies for carrying on with an affair while he was on duty.

Deputy Todd Saunders was fired Thursday for on-duty misconduct for carrying on the affair, spending long periods of time at a woman's house while he was supposed to be patrolling in the West Plains area.

"The allegation is that this particular deputy has been parking at a residence in the county and has been staying in that residence for extended periods of time, during his shift," Spokane County Sheriff Ozzie Knezovich said when the allegation first came to light in late March.

Saunders was supposed to be patrolling the area south of Interstate 90 in the Cheney area on the graveyard shift, but residents in one neighborhood became suspicious when they saw a fully marked sheriff's patrol car parked at one home for long periods of time. One resident reported what he saw to a deputy, who in turn reported it to his sergeant, and subsequently an internal affairs investigation was launched.

Saunders reportedly left his patrol car running when his car was parked, and also was seen putting his patrol car in the garage of the residence.

A subsequent investigation showed Saunders would gather random license plate number from the Cheney area and then periodically run them on his computers so it appeared he was out on patrol.

"It really comes down to the fact that Deputy Saunders really broke the public's trust and he left the public very much unprotected when he was at this house. He should have been out patrolling this area and being proactive," Knezovich said Thursday.

The woman who lives in that residence where he was parking is not Saunders' wife and refused to cooperate with investigators.

The sheriff's office has issued an apology to those car owners who had their plates ran by Saunders in an attempt to cover up what he was really doing.

Saunders could potentially face criminal charges. Sheriff Knezovich said he can prove Saunders was stealing from taxpayers by collecting hourly wages he wasn't earning and the Spokane County Prosecutor's Office could consider filing theft charges against him.