Authorities have identified the teenager who stabbed four people on the campus of UC Merced as Faisal Mohammad, an 18-year-old freshman from Santa Clara, Calif.

Mohammad was a computer science and engineering student living on campus, Claudia Cowan reported Thursday afternoon on “Happening Now.”

Officials say he used a 9-inch hunting knife to attack four people before he was fatally shot by campus police on Wednesday.

Two victims were airlifted to a hospital, while two were treated at the scene. 

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Mohammad reportedly first launched his assault inside a classroom, where a nearby construction worker heard the commotion and ran in, thinking it was a fight.

That worker, 31-year-old Byron Price, was also stabbed.

Price is now being praised for helping protect a student’s life, said Cowan.

He described the scene to CBS Fresno, saying that Mohammad “had a smile on his face” during the attack.

“He was having fun,” he added.

The violence didn’t end there. Officials say Mohammad moved outside, where he continued to stab two more people.

When he began to approach campus police, he was shot and killed.

A student who knew the attacker told KFSN-TV that he was quiet and kept to himself.

"Every time I would try and say something he would just ignore it," said Andrew Velasquez, a dorm suitemate of Mohammed's.

Authorities have not said what Mohammad's motive was. 

See more about this story in the clip above.

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