Roger Dennis Seela entered the plea in King County Superior Court, where he is charged with second-degree murder, and was ordered held on $1 million bail.
Court papers filed in the case say the body of Seela's former girlfriend, April Frederick, was found on the railroad tracks near a transient camp on July 2, 2013.
An autopsy showed that she had died from strangulation and blunt force trauma to the head and then apparently was dragged to the tracks from the nearby camp.
Seela, who lived in the transient camp near the tracks, was questioned by police shortly after Frederick's body was found. He was extremely intoxicated and had blood on his shoes, court documents say. He told officers that he had been assaulted a few days before and the blood was his own.
A few hours later he was interviewed again, after he had sobered up somewhat, and told police he had been drinking with friends all night and knew nothing about Frederick's killing.
Investigators then discovered that Frederick had a history of domestic violence with Seela. They also found that Seela had an earlier second-degree assault conviction in which he attacked a victim with a pair of scissors, as well as four prior fourth-degree assault convictions.
Seela was interviewed again and told police that he didn't know Frederick was the murder victim. He said she had lit him on fire some days before and thought she was still in jail for that. He continued to deny any knowledge of the murder and was released, according to court documents.
Then, earlier this month, police received a crime lab report showing that the blood on Seela's shoes matched Frederick's DNA. Swabs from Frederick's neck and ankles also matched Seela's DNA, court documents say.
Seela was arrested and booked into the King County Jail for investigation of second-degree murder. His next court appearance is set for May 1.