Raymond Thomas had been dead for nearly 10 years when James King walked into the 18th District police station Sunday night.
Thomas was 24 when he was killed on Dec. 16, 2004 - over drugs, police say. When he was found, he was dead of a gunshot wound, tied up, on the third floor of his home in the Cedar Park section of West Philadelphia.
Thomas was lying on top of his one-year-old son, who had been bound at the ankles with surgical tape but was otherwise unharmed.
The child's mother, Thomas' girlfriend, found them both when she arrived home from work and called police.
Thomas was pronounced dead at the scene.
For years, his murder was unsolved - until King unexpectedly showed up at the police station and admitted his involvement in the killing on Sunday, police said.
King's named had come up during the investigation a decade ago, Homicide Capt. James Clark said. But the 33-year-old from West Philadelphia was not being sought in the murder.
"He just turned himself in," Clark said.
Clark said it appears that King "just wanted to clear his conscience and get it off his chest." King has been charged with murder and related offenses.
King has been arrested several times, before and after the murder, and had convictions on theft, drugs and firearms charges. He has a preliminary hearing scheduled for Oct. 15.