RECOMMENDED: A Second Amendment quiz
Law officers said during a Wednesday press conference that they did not know whether any member of the public carrying a concealed weapon had counterattacked Roberts. But they said they are certain that Roberts died by his own hand after fleeing down a stairwell from the mall's upper level.
The death rate from mass shootings has ticked up slightly in recent years, even as deaths in single-victim incidents have decreased, according to a recent analysis of FBI crime data by the Huffington Post. The worst recent mass shooting came in July in Aurora, Colo., where a gunman killed 12 people and injured 58 during a midnight screening of a new "Batman" movie.
Gun-control advocates seized on the mall shooting as a possible result of the expiration in 2004 of a national ban on assault weapons.
"Santa Claus could have been shot in the mall," said Penny Okamoto, executive director of Ceasefire Oregon, in an interview with the Portland Tribune. "If you're sick of this, you should call your legislators to tell them to fix the laws so that assault weapons don't end up in the hands of felons."