The officer, who has spent more than 20 years with the department, is accused of molesting his former girlfriend's daughter on several occasions between 2009 and 2013, according to the Snohomish County Sheriff's Office.
A source within the Seattle Police Department confirmed the officer is Eric Smith, who works in the department's traffic division.
Deputies arrested the 57-year-old Bothell resident on Monday following a two week investigation into the case. He's now facing charges of first degree child molestation and communicating with a minor for immoral purposes.
Deputies say the victim in the case was between 7- and 11-years old when the alleged crimes were committed.
Smith's neighbor Bryan Leonard said he was stunned to learn of the arrest.
"Well it's a little shocking. You never want to hear that of someone who's a neighbor," he said. "I hope for the girl's sake, the little girl's sake, it's false."
Seattle police officials were made aware of the investigation on June 18 and immediately put the officer on administrative leave, according to police.
Detectives are continuing with the investigation.
"Obviously they want the investigation to be thorough, but they want to move quickly," said Shari Ireton with the Snohomish County Sheriff's Office.
Smith is due in Snohomish County Court on Tuesday.