Police in Oregon have arrested David Kalac, the man accused of brutally murdering his girlfriend and posting gruesome pictures of the scene on the Internet. (Reuters)

It’s hard to know what’s real and what’s not on the Internet, particularly on Web sites as notoriously murky as 4chan, from whence came the hacked nude celebrity photos a few months ago that created such a stir.

So when gruesome-looking photos of what appeared to be the lifeless body of a nude woman with red marks around her neck appeared on 4chan on Tuesday, nobody was quite sure what to make of them. According to the Los Angeles Times, the photos were accompanied by this cold-blooded statement: “Turns out it’s way harder to strangle someone to death than it looks on the movies. … She fought so Damn hard.”

Was it a hoax? What sort of person would take such pictures and post them? Police in Washington state now think they know the answer.

The pictures were real. The woman was murdered Tuesday. And the man who allegedly posted the photos turned himself in last night.

Authorities told reporters Amber Lynn Coplin of Port Orchard, Wash., was the woman in the photos — and the man who likely took and posted them was her boyfriend, David Michael Kalac, 33, who has been charged with murdering her in the apartment they shared.

Kalac turned himself in to police in Clackamas County, Ore., shortly before 9 p.m. last night, Portland police said.

Kalac is “our primary suspect,” Kitsap County Sheriff’s Deputy Scott Wilson said. “It stands to reason that in all likelihood he is the person who posted those photographs.”

Coplin’s 13-year old son found his mother’s body in her apartment Tuesday, Wilson told KOMO News. Her driver’s license was nearby with the word “dead” written on it. The boy told police he had heard Kalac and his mother arguing loudly Monday night. Other witnesses reported hearing thumping and banging noises coming from the apartment, just west of Seattle.

Kalac reportedly texted a friend afterwards saying he would read about him in the news. Police also said Kalac wrote he was hoping to die from “suicide by cop.”

“Check the news for Port Orchard Washington in a few hours,” Kalac allegedly wrote. “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. I understand the doubts. Just check the f—— news. I have to lose my phone now.”

At some point, he took off in Coplin’s car and police began a manhunt.

As for the photos, Wilson said they were probably posted about half-an-hour before the death was reported Tuesday. According to a court affadavit reported by NBC News, police said the photos matched the woman, her injuries and the crime scene.