The last person to be charged with the killing of Ritche Clark in March 1999 changed his plea to guilty of second-degree murder, the U.S. District Court office in Denver confirmed this week.

Alden P. House, 18, was charged by a federal grand jury last May with second-degree murder and aiding and abetting in that offense. House, a juvenile at the time of the murder, was found by federal prosecutors and U.S. District Court Judge Lewis T. Babcock May 28 to be competent to be tried as an adult.

He originally pleaded innocent to the charges and a trial date was set for this month, but he changed his plea on July 28 to guilty of second-degree murder. A sentencing hearing is set for Oct. 6.

House, along with Karla Silas and Thomas Tom, beat Clark to death during a drunken altercation sometime between Feb. 28 and March 2 in a wooded area at the foot of Sleeping Ute Mountain, according to police and FBI affidavits.

No motive was ever determined.

Tom and Silas both pleaded guilty for their roles in Clark’s killing and were sentenced to federal prison.

Silas, 29, is serving a four-year sentence after accepting a plea bargain to accessory after the fact to second-degree murder. Her vehicle was used to transport Clark’s body to a nearby ditch in an attempt to hide the body, according to FBI reports.

Tom, 25, admitted to participating in the beating death of Clark. He is serving a seven-year, three month sentence in federal prison for second-degree murder.

Both Silas and Tom agreed to testify against House, who according to witnesses quoted in police reports, delivered the final blow to Clark, using a log.

After hearing from family and friends who had heard of the incident, police and rescue teams conducted a search of the area, finding Clark’s body on March 3 three miles north of Towaoc.