The robbery happened around noon May 24 at Whidbey Island Bank.
A man with a handgun physically assaulted a teller during the holdup, Snohomish County Sheriff’s Office spokeswoman Shari Ireton said.
The suspect remained at large as of Thursday.
Witnesses described the assailant as a man in his late teens or early 20s. He wore black tape across his nose, a gray “hoodie” sweatshirt, a beige shirt and jeans.
After the robbery, he ran south on 72nd Avenue NW.
Anyone with information is asked to call 425-388-3845. Callers can remain anonymous.