Norman, Okla. ? A University of Oklahoma student with “emotional difficulties” was identified Sunday as the person who was killed when an explosive attached to his body detonated near a packed football stadium, authorities said.

The body is believed to be that of Joel Henry Hinrichs III, 21, Salvador Hernandez, FBI special agent in Oklahoma, said in a news release.

“We know that he has had what I would call emotional difficulties in the past. And as I said, this is an individual death. There is certainly no evidence at this point which points to any other kind of motivation other than his personal problems,” OU President David Boren told reporters Sunday afternoon.

Boren declined to say where Hinrichs was from, but a student telephone book lists a permanent address in Colorado Springs, Colo.

Hinrichs’ father, Joel Henry Hinrichs Jr., said he was surprised to hear about his son.

His son was a National Merit Scholar who graduated in May 2002 from Wasson High School in Colorado Springs and began attending OU in the fall of that year with a major in mechanical engineering.

Authorities haven’t identified what kind of explosive device was used. Boren initially said a second explosive device was detonated by a bomb squad Saturday night but later said no other devices had been discovered.

The explosion occurred around 8 p.m. Saturday while Hinrichs sat on a bench outside George Lynn Cross Hall, officials said.

Authorities cordoned off the area west of the stadium and no one was allowed to leave the facility immediately after the blast for security reasons. Spectators were allowed to go outside about 30 minutes later.

Boren said he expected the area to be opened today and classes would be unaffected.

The Kansas State-Oklahoma football game, which was in the second quarter at the time of the explosion, went on without interruption, and no announcement was made until the final minutes of the game.