David Kalac: 4chan murder suspect arrested after woman is killed and pictures of her corpse are posted on website

Amber Lynn Coplin was found dead in the Port Orchard apartment she shared with Kalac

David Kalac, 33, who police say is a suspect in the killing of a woman in Port Orchard, Washington (AP)

A man suspected of strangling his girlfriend to death after images of her nude corpse and details of how she was killed were posted on 4chan has turned himself in, police have said.

Police in Portland, where the dead woman's car was found Wednesday afternoon, confirmed that 33-year-old David Kalac has been detained and charged with second-degree murder.

An officer was patrolling the Wilsonville area when Kalac came out of a wooded area near a parking lot and handed himself in.

Amber Lynn Coplin, 30, was found dead in her apartment in the town of Port Orchard by her 13-year-old son on Tuesday afternoon. Kalac and Ms Coplin, a mother-of-four, are understood to have been living together with the teenage boy in the apartment.

Photos of Ms Coplin’s body had been posted on the internet forum 4chan by an anonymous user before her body was found, along with messages detailing her killing.

Police say they discovered Coplin's body in a bedroom. Her driver's license was found next to her head with the word "dead" written on it. “Bad news" was written on the blinds and "she killed me first" was scribbled on a picture on the wall.

Deputy Scott Wilson with the Kitsap County Sheriff's Office said detectives confirmed the gruesome photos posted on the website are of the victim and the crime scene.

Posts accompanying the pictures allegedly said: "Turns out it's way harder to strangle someone to death than it looks on the movies. She fought so damn hard."

The user also described a plan to be killed by police on the forum, writing: “Her son will be home from school soon. He’ll find her, then call the cops. I just wanted to share the pics before they find me. I bought a BB gun that looks realistic enough. When they come, I’ll pull it and it will be suicide by cop.”

According to investigators, Kalac had allegedly sent his friend a text on Tuesday morning telling him he would read about him in the news. The text allegedly read: "You'll see me in the news...There will be no more me. Ever. You'll read about it. That's all."

The Kitsap County Coroner will conduct an autopsy today to determine Ms Coplin’s cause of death.

Additional reporting by the Associated Press