CHENEY, Wash. -

A Spokane County sheriff's deputy has been accused of on-duty misconduct and is suspected of having an affair with a woman while he was supposed to be on patrol.

Deputy Todd Saunders is under investigation for having an affair while he was supposed to be patrolling the West Plains area.

A neighbor, who said the trysts happened often, actually used a calendar to keep track of Saunders' visits to a residence. That person got fed up with the deputy's blatant disregard for his duties and gave the information to the sheriff's office, which immediately launched an internal-affairs investigation into Saunders and his alleged on-duty dalliances.

"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.

Saunders was supposed to be working his graveyard shift south of Interstate 90 in the Cheney area. Several months ago neighbors began taking note of a fully marked green and white patrol car spending a lot of time at one particular house. The neighbor told another deputy, who reported the suspicious circumstances to his sergeant, prompting the investigation.

Saunders allegedly left his patrol car running during the period his car was parked, and also was observed putting his patrol car in the garage of the residence. The woman who lives in that residence is not Saunders' wife, and Knezovich said that woman is refusing to cooperate with internal affairs investigators.

The sheriff says Saunders has disgraced his fellow deputies for his own selfish pleasures and if these allegations are substantiated, he'll fire Saunders from the force.