A 19-year-old man has killed eight people after opening fire with a rifle in a shopping mall in Omaha, Nebraska. Mike O'Sullivan reports, police say the gunman also injured five other people, two of them critically, before taking his own life.

Witnesses say the shooter fired on holiday shoppers from a third-floor balcony of a busy department store. Some people fled and others barricaded themselves in dressing rooms or hid beneath clothing racks.

One witness told NBC News what he heard.

"I heard bang, bang, bang. I probably heard 12 to 15 shots," he said.

Another witness said he heard more than 30 shots.

Police say the gunman died of a self-inflicted wound. They believe that he acted alone.

Omaha police chief Thomas Warren says authorities recovered an SKS assault rifle. They identified the shooter as 19-year-old Robert Hawkins of Bellevue, Nebraska.

"We are in the very preliminary stages of this investigation and our immediate attention will be devoted to processing the crime scene," said Warren. "We will also be in the process of establishing positive identification of the victims and notifying their next of kin."

Reports say the gunman's mother had brought police the gunman's suicide note, indicating he was despondent and wanted to "go out in style."

Local news reports says the man was recently fired from a job in a fast food restaurant and had broken up with his girlfriend. Police declined to speak of a possible motive.