BOULDER, Colo. -- A University of Colorado football player has been arrested, accused of beating up another CU student with a rock during a party in an off-campus apartment.

Lynn Katoa, 18, turned himself in Friday and is being held for investigation of second-degree assault.

Police were called to an apartment at Euclid Avenue and 12th Street early Feb. 16 on a report of an assault. Witnesses said a member of the football team came through the door, yelling, then pushed one victim's head into the wall and hit him in the forehead while holding a rock in his fist. Witnesses said the football player then punched a second victim in the head.

The first victim, Cameron Shafer, was taken to the hospital for stitches. The second victim declined to pursue charges and was not identified.

When officers arrived, the football player and others involved in the fight were not there but witnesses identified him as Katoa. Investigators also learned that the fight stemmed from an altercation that had occurred outside the apartment building a short while earlier.

During the first fight, one of Katoa's friends was shocked by a stun gun, which angered Katoa. The men with the stun gun took off in a vehicle while others chased them. Katoa allegedly picked up a rock and stormed inside the apartment to confront others, police said.

The men involved in the stun gun incident have not yet been identified.

Katoa was booked into the Boulder County Jail with bail set at $5,000.

"We are mentoring our student athletes to be first class people, students, and athletes. I do not condone our players engaging in violent personal altercations, or any illegal or unethical conduct. Lynn will be suspended from competition, though I will permit him to practice, until everything is resolved. I will support both the legal system and our internal process with the Office of Judicial Affairs," said CU football coach Dan Hawkins.

Katoa is a freshman linebacker who graduated from Salt Lake City's Cottonwood High School in December 2007 and enrolled early at CU. He was recruited by Texas, Oklahoma, Oklahoma State, Florida and Miami. Katoa first started playing football as a junior in high school and got to where he is because of his athletic ability and raw instincts, according to online scouting reports.

Anyone with information about the incident is asked to contact Detective Kristi Peterson at the Boulder Police Detective section at 303-441-3330. Those with information who wish to remain anonymous should contact Boulder County Crime Stoppers at 1-800-222-TIPS (8477) or 1-800-444-3776. Tips can also be submitted via the Crime Stoppers Web site. Those submitting tips through Crime Stoppers that lead to the arrest and filing of charges on a suspect(s) may be eligible for a cash reward of up to $1,000 from Boulder County Crime Stoppers.