The University of Oklahoma says it's tightening security at Oklahoma Memorial Stadium after a student with explosives attached to his body died in a blast nearby.

Twenty-one-year-old Joel Henry Hinrichs the Third of Colorado Springs died Saturday when an explosive device attached to his body went off. It happened within one hundred yards of the stadium as thousands of fans watched a football game there.

Boren says authorities continue to believe that Hinrichs did not try to get into the stadium and that he acted alone.

Hinrichs' father has said he's confident his son committed suicide, and that he didn't intend to harm anyone else.