Police on the west coast of the US have launched a manhunt after the decapitated body of a woman was discovered close to a survivalist bunker.

The headless body of 26-year-old Katherine Cunningham was discovered on Saturday (3 March) on Tamarack Lane, on the rural Camano Island, north of Seattle, in northwest Washington state.

The woman's remains were found close to a survivalist bunker that was dug into a hill which contained firearms and ammunition, police have said.

An autopsy conducted on Tuesday determined the cause of death as "Homicidal Violence with Decapitation," according to the Stanwood Camano News.

Authorities say they want to speak to a person of interest, named as Jacob Gonzales a 34-year-old man who is currently missing and believed to be armed.

The force added that investigators recovered a "cache of supplies, firearms and ammunition" from the hillside bunker.

Police did not elaborate on the connection between Gonzales and Cunningham and said that she died a few days before her body was found on Saturday.

"Based on the evidence it appears that the victim was specifically targeted and this was not a random act," the Island County Sheriff's Office said in a statement cited by The Seattle Post-Intelligencer.

"We are developing leads on a person of interest in the case and hope to release that information in the near future."

Police say that Gonzales may be heading for southern or central California and have asked the public not approach him.

"Based on information coming in from various tips it appears that Gonzales may be driving a silver compact car with an unknown license plate," the Island County Sheriff's Office announced on Thursday (8 March).

Gonzales is said to be a Hispanic male, roughly 5ft 9" tall, weighing around 150 pounds with black hair and hazel eyes.

Police added that a Mitsubishi Montero, which he was initially thought to be driving, has been located.