"Sources identified the dead suspect as Wade Michael Page, who was at one time attached to the Fort Bragg Army installation in North Carolina," Fox News said.
According to eyewitnesses, Page had a 9/11 tattoo on his arm. They said that he walked into the gurdwara in Milwaukee's Oak Creek suburb even as Sikhs were gathering there and started firing indiscriminately.
Page killed six persons and injured three others before a policeman's bullet claimed his life. The senseless shooting left the Sikh community in shock.
The local police described it as an act of "domestic terrorism" but the Federal Bureau of Investigation (FBI) said that "no motive has been determined" as of now.
Federal agencies including the FBI are currently probing the incident that has been condemned by both the Indian and American governments.
After reviewing the security situation with his top aides, US President Barack Obama called on the gurdwara trustee to offer his condolences.
"Michelle and I were deeply saddened to learn of the shooting that tragically took so many lives in Wisconsin," Obama said.
US Deputy National Security Advisor John Brennan spoke to Indian Ambassador Nirupama Rao and conveyed his country's "sincerest condolences".
She later tweeted: "Mr Brennan assured me these tragic killings would be fully investigated, that Sikh community is precious part of fabric of American nation."