A Corvallis Police officer who quit the department two years ago amid allegations that he had an on-duty affair with an Oregon State University student and lied to his superiors about it pleaded guilty Friday to two charges of official misconduct.

Ryan Thayer, 27, had worked for CPD for three years before he resigned in 2006 for “personal reasons.”

Thayer, who was married, resigned in April 2006 after allegations surfaced that he had violated 21 department regulations. The most serious were that he had sex with the woman while he was supposed to be on patrol, lied to supervisors about his whereabouts and activities, disobeyed orders and used a department cell phone to talk with the woman.

The department opened an investigation into the matter in March 2006 and placed Thayer on administrative leave, but it appeared to have let the matter drop after he resigned.

On Friday, Thayer appeared in Benton County Circuit Court to accept a plea deal that dismissed four of the six charges of official misconduct. One charge was downgraded to a violation from a Class A misdemeanor but it still carries a $457 penalty.

In the conditional discharge, Thayer agreed to a 24-month probation that prohibits him from working or even applying for a job in law enforcement. He also is required to perform 40 hours of community service.

District Attorney John Haroldson said the case might have been delayed while waiting for the Corvallis Police to complete an internal investigation, and for a special prosecutor to be able to clear his schedule in order to travel out of town.

Stephen Morgan of the Lane County District Attorney’s Office was appointed as a special prosecutor in the case in order to absolve the Benton County District Attorney’s Office of any conflict of interest.

The case, which had not been filed with the court for nearly two years after Thayer’s resignation, did not begin until January 2008. Thayer agreed to the plea deal just three days before a jury trial was set to begin.

Morgan and Thayer’s attorney, Clark Willes, could not be reached for comment on Friday.