Bellevue, Neb. ? A high school dropout with a criminal past, Robert A. Hawkins had struggled to overcome depression. But friends thought he was making strides.

Then, about two weeks ago, he lost his girlfriend. A week later, it was his job. His friends worried he would regress.

“He was a very helpful young man, but he was quiet,” said Debora Maruca-Kovac, a surgical nurse whose family took in Hawkins after her 17- and 19-year-old sons befriended him.

“He didn’t cause a lot of trouble. He tried to help out all the time,” Maruca-Kovac said. “He was very thankful for everything. He wasn’t a violent person at all.”

But police said it was Hawkins who went into an Omaha shopping mall on Wednesday and began a shooting rampage that killed eight people. It ended when he turned his high-powered rifle on himself. The rampage was as troubling as it was puzzling for those who knew him.

Hawkins, 19, had been in trouble before. There was a felony drug conviction in March 2005 and the disorderly conduct charge seven months later. He was due in court later this month on charges he contributed to the delinquency of a minor.