The sergeant was arrested on Oct. 13 at a home on Oleary Road, off of English Road in Conway after Skagit County deputies executed a search warrant.
The Skagit County Sheriff's Office said the sergeant was off duty at the time of both alleged incidents and knew both victims.
Detectives conducting the investigation were able to establish probable cause for rape, in consultation with the Skagit County Prosecuting Attorney’s Office, and are continuing their investigation into the matter.
The sergeant was taken into custody without incident and will be booked into the Skagit County Community Justice Center for an investigative hold for second-degree rape.
The Island County Sheriff's Office will also hold an internal review to see if the sergeant violated county policy. The Skagit County Sheriff's Office will conduct the criminal investigation.
"Given the seriousness of the allegations and consistent with Island County policy and practice, Sgt. was immediately placed on administrative leave pending the criminal investigation. The allegations, if true, would also constitute serious violations of County policy," the Island County Sheriff's Office wrote on Facebook.