Officers with search dogs were called to the scene and recovered a gun. Police arrested 19-year-old Niajel Slade and 17-year-old Aaron Ramsey.
An ABC11 viewer reported the shooting happened about 45 minutes before part-time mall security guards arrive for their 4 to 9 p.m. shift. The viewer also said the mall cut that security shift last month.
Security officials wouldn't comment about Monday's shooting or about cuts to security.
The shooting follows a long list of incidents at Northgate including a fatal double shooting in a parking deck in 2002 and a fatal stabbing in 2007.
The stabbing was the fifth violent fatality at Northgate in five years. Investigators have said all of the incidents were provoked by fights. There were reports that a fight may have sparked Monday's shooting.