CROWN POINT, Ind. (AP) — A teenager pleaded not guilty Monday to murdering another student, and his attorney said the fatal shooting last week was an act of self-defense.

"There was bullying going on and intimidation," said defense attorney Walter Alvarez, who declined to cite a specific provocation for the shooting. "There are so many different ones we really can't pinpoint an accurate one."

Donald Ray Burt Jr., 17, was charged as an adult and ordered to remain in jail without bail. If convicted, he faces up to 65 years in prison.

Neal Boyd, 16, was killed Friday outside Lew Wallace High School in Gary, Ind. Investigators said Burt, who no longer attended the school, crossed the school lawn, approached Boyd and after a brief exchange shot him once.

Burt was arrested about 45 minutes later at his sister's home several blocks away.