KOMO/ABC News

A Washington police sergeant who allegedly had sex with a prostitution ring leader in exchange for giving her information on undercover police operations has resigned.

Darrell O'Neill, 58, of Everett, Wash., resigned on Tuesday afternoon, Shari Ireton, director of communications for the Snohomish Sheriff's Office, told ABC News.

In June, police discovered that O'Neill had given the members of a prostitution ring operating out of bikini barista stands in Snohomish County information regarding undercover investigations targeting the activity, authorities said. In exchange for his information, O'Neill received sexual favors from the baristas and stand managers, according to a police report filed in Snohomish County.

O'Neill was arrested and charged in June with promoting prostitution and official misconduct, according to Ireton.

The Snohomish Sheriff's Office deferred to an outside agency, the Everett Police Department, to oversee the case, Ireton said.

"O'Neill's actions leading up to his arrest last month by the Everett Police Department for conspiracy to promote prostitution and official misconduct had been under investigation by the Office of Professional Accountability. Any criminal charges as a result of that investigation will be filed by the Snohomish County Prosecuting Attorney's Office," Ireton said in a statement.

The Snohomish County Prosecuting Attorney's Office and O'Neill did not respond to requests for comment.