A man charged with killing his girlfriend and posting pictures of her body online and writing that he wanted authorities to find and kill him walked up to an officer Wednesday night and surrendered, police said.

David Kalac, 33, was arrested at a transit center in Wilsonville, about 20 miles (30 kms) south of Portland, Clackamas County sheriff's Sgt. Nate Thompson said.

An officer was patrolling the area when a man came out of a wooded area near a parking lot.

"He basically said, 'I have a warrant for my arrest,'" Thompson said in a telephone interview.

Police in Wilsonville said Kalac was cooperative. He was charged with second-degree murder in the slaying of Amber Lynn Coplin, found dead Tuesday in her apartment in Port Orchard in the neighboring state of Washington.

Kalac was believed to have fled in her car, which was found abandoned Wednesday afternoon in Portland, about 160 miles south of the crime scene.

Kalac has a criminal history in Washington state and Virginia that includes convictions for assault, burglary and drunken driving, Kitsap County, Washington, sheriff's Deputy Scott Wilson said.

Deputies have confirmed that gruesome photos posted on a website are of the victim and the Port Orchard crime scene, Wilson said.

"He's our primary suspect," Wilson said Wednesday. "It stands to reason that in all likelihood he is the person who posted those photographs."

Coplin's body was found by her 13-year-old son, Wilson said.

Hours earlier, the boy had heard her arguing with Kalac, detectives said in court papers. An arrest warrant was issued Wednesday.

Police say they found Coplin's body in a bedroom. Near her head was her driver's license with the word "dead" written on it. The words "bad news" were written on blinds. And the words "she killed me first" were written on a picture on the wall.

The teenager told police he thought his mom was sleeping in and Kalac was gone when he left the apartment Tuesday morning, according to court documents.

According to Wilson's account, the boy came home from school Tuesday morning and took a nap. When he woke up that afternoon, he noticed the car was missing, went to check on his mother and "found her unresponsive," Wilson said.

The teen then called his father, Coplin's estranged husband, and he alerted authorities, the sheriff's spokesman said.

Wilson said investigators believe Kalac is the sole suspect in Coplin's death and they are not looking for any accomplices.