The shooter who killed five students at Northern Illinois University on Thursday was a lauded sociology student who earned the Dean's Award in 2006, the Chicago Sun-Times reported.

Police identified the gunman as Steven Kazmierczak, 27. He transferred last year to the University of Illinois in Champaign-Urbana.

"He had stopped taking medication and become somewhat erratic in the last couple of weeks," NIU Campus Police Chief Donald Grady said.

Kazmierczak had a shotgun and three handguns during the attack, police said Friday.

The gunman, a former vice president of NIU's Academic Criminal Justice Association, wrote about social justice on an Internet site, the paper said.

Kay Forest, the head of NIU's sociology department, said Dean's awards are only given to "really good students," the Sun-Times reported.

In a paper he helped write two years ago, he described his interests as social justice, corrections, political violence and peace, the Sun-Times said.

Clad in black, Kazmierczak walked into a lecture hall Thursday and indiscriminately fired on a science class, sending students diving to the floor and running toward the exits.

Five people were killed and 15 wounded. Kazmierczak killed himself.

The Associated Press contributed to this report.

Click here to read the Sun-Times report.