Darrell O'Neill was one of nine people arrested in June as part of a months-long investigation into lewd conduct and prostitution at the so-called bikini barista stands.
While interviewing some of the detained baristas, detectives learned O'Neill was tipping off workers as to when it was safe to "put on a show," police said.
"He was providing law-enforcement sensitive information on when undercover operations were being conducted and even some of the makes and models of an undercover vehicle," Everett Police Deputy Chief Dan Templeman said after the arrests.
One barista, in court documents, told investigators she saw O'Neill having sex inside one of the stands, but Everett police say they never witnessed that during their surveillance.
The surveillance footage did show O'Neill hugging and kissing several of the baristas. Detectives called O'Neill's arrest the ultimate violation of public trust.
On Tuesday afternoon, Snohomish County sheriff's office officials announced O'Neill had resigned. Any criminal charges he may face in connection with the case would come from the Everett Police Department.