A suspect looked for over a deadly firearm assault at a mall in Washington state on Friday evening has been caught, police say.

Police have named him as Arcan Cetin, 20, of Oak Harbor, Washington. He was conceived in Turkey and is a lawful US lasting inhabitant, authorities say.

The capture occurred in Oak Harbor, a town south-west of Burlington where the shooting happened.

Five individuals were executed inside Macy's retail establishment at Cascade Mall.

The FBI said there was no confirmation that the shooting was connected to fear mongering.

At a news gathering, police said Arcan Cetin had been recognized as a suspect after an auto associated with him was seen on security camera footage at the mall.

Lt Mike Hawley, of Island County Sheriff's Department, said the auto was later seen in Oak Harbor. He said he had been headed to the scene when he saw the associate by the side with a street and captured him.

Lt Hawley said the man "said nothing, he was zombie like" and was not conveying a weapon.

As such, police say they know of no thought process in the shootings.