Steven Kazmierczak, 27, opened fire in a geology class last Thursday at the university. He was a graduate student at the University of Illinois studying sociology.

Jessica Baty, Kazmierczak's girlfriend, told CNN "he was normal," adding that although he had a history of mild psychological problems, "he wasn't delusional."

Baty said Kazmierczak stopped taking his anti-depressants three weeks ago because "it made him feel like a zombie."

He purchased at least two guns that Baty knew of but he told her he was going to use them for home protection.

"The Steven I know and love was not the man that walked into that building," she said. "He was anything but a monster. He was probably the nicest, most caring person ever."

She said he wrote her a note before the attack that read in part, "Don't forget about me! Love, Steven Kazmierczak."