Wade Michael Page, who was himself shot dead by police during the incident, was a 40-year-old who had served between April 1992 and October 1998, ending his career at Fort Bragg, North Carolina.
Witnesses said the gunman opened fire when he entered the kitchen at the Sikh Temple of Wisconsin in suburban Milwaukee as women prepared a Sunday meal, sending worshippers fleeing to escape the barrage.
Four people were shot dead inside the sprawling temple. Three, including the gunman, were killed outside.
The gunman ambushed and shot a police officer who was responding to a 911 call and helping a shooting victim, Oak Creek Police Chief John Edwards said. A second officer shot and killed the gunman.
Edwards said he had no identification for the shooter nor information on what kind of weapon or weapons he had. The victims’ identities and descriptions were not made public.
The wounded officer, a 20-year veteran, was taken to a hospital and is expected to survive. Hospital officials said two other victims, also in critical condition, were being treated.
Law enforcement personnel surrounded and searched a gray, two-storey house in the Cudahy neighborhood presumed to be the residence of the gunman on Sunday evening. Generators and floodlights were set up along the middle-class block.
A police source confirmed that a search warrant had been issued for the house, and a bomb squad was on the scene.
Temple member and U.S. Army Reserve combat medic Jagpal Singh, 29, said people who were at the service when the shooting broke out described to him a scene of chaos and confusion.
Worshippers scrambled to escape the gunfire, but some tragically ran in the wrong direction. Others survived the rampage by locking themselves in bathrooms, he said.
Singh said eyewitnesses described the shooter as a white man who was either shave-headed or bald.