A shooting at a Walmart in Mississippi has left two people dead and a police officer injured. Officials say the male suspect, whose name has not been released, was a former employee of the store who had a personal grievance with a manager. The suspect was shot two times during a stand-off with the injured officer, who was shot once. Both are being treated at local hospitals. Police said their recent active shooter training prevented more deaths. Walmart issued a statement offering condolences to the victims and their families.