The gunman who killed six people at a Sikh temple in Wisconsin before being shot to death by police was identified Monday as a 40-year-old Army veteran and former leader of a white supremacist heavy metal band.

Authorities said Wade Michael Page strode into the temple without saying a word and opened fire using a 9mm handgun and multiple magazines of ammunition.

Page joined the Army in 1992 and was discharged in 1998, according to a defense official who spoke to The Associated Press on condition of anonymity because he was not yet authorized to release the information.

Witnesses said the gunman walked into the Sikh Temple of Wisconsin in suburban Milwaukee and opened fire as several dozen people prepared for Sunday services. When the shooting ended, six victims ranging in age from 39 to 84 years old lay dead, as well as Page. Three others were critically wounded.

Page was a "frustrated neo-Nazi" who led a racist white supremacist band, the Southern Poverty Law Center said Monday.

Mark Potok, a senior fellow at the nonprofit civil rights organization in Montgomery, Ala., said Page had been on the white-power music scene for more than a decade, playing in bands known as Definite Hate and End Apathy.

"The name of the band seems to reflect what he went out and actually did," Potok said.

"There is a whole underworld of white supremacists music that is rarely seen or heard by the public," Potok said, describing lyrics that talk about carrying out genocide against Jews and other minorities, he said.

Potok said there's no research showing white supremacists hating Sikhs, indicating that Sunday's attack was almost certainly an example of someone mistaking Sikhs for Muslims.

In a 2010 interview, Page told a white supremacist website that he joined the white-power music scene in 2000, when he left his native Colorado and started the band End Apathy in 2005.

He told the website his "inspiration was based on frustration that we have the potential to accomplish so much more as individuals and a society in whole," according to the law center. He did not mention violence in the website interview.

End Apathy's biography on the band's MySpace page said it was based in Nashville, N.C.

Joseph Rackley of Nashville, N.C., said Monday that Page lived with his son for about six months last year in a house on Rackley's property. Wade was bald and had tattoos all over his arms, Rackley said, but he doesn't remember what they depicted. He said he wasn't aware of any ties Page had to white supremacists.

"I'm not a nosy kind of guy," Rackley said. "When he stayed with my son, I don't even know if Wade played music. But my son plays alternative music and periodically I'd have to call them because I could hear more than I wanted to hear."

Page joined the military in Milwaukee in 1992 and was a repairman for the Hawk missile system before switching jobs to become one of the Army's psychological operations specialists, according to the defense official.

So-called "psy-ops" specialists are responsible for the analysis, development and distribution of intelligence used for information and psychological effect. Fort Bragg, N.C., was among the bases where Page served.

The FBI, which was leading the investigation because the shootings are being treated as domestic terrorism, or an attack that originated inside the U.S., said it had no reason to believe anyone other than Page was involved.

Satpal Kaleka, wife of the temple's president, Satwant Singh Kaleka, was in the front room and saw the gunman enter the temple, according to Harpreet Singh, their nephew.

"He did not speak, he just began shooting," said Singh, relaying a description of the attack from Satpal Kaleka.

Kaleka said the 6-foot bald white man — who worshippers said they had never before seen at the temple — seemed like he had a purpose and knew where he was going.

"We never thought this could happen to our community," said Devendar Nagra of Mount Pleasant, whose sister escaped injury by hiding as the gunman fired in the temple's kitchen. "We never did anything wrong to anyone."

Late Sunday, the investigation moved beyond the temple as police, federal agents and the county sheriff's bomb squad swarmed a neighborhood in nearby Cudahy, evacuated several homes and searched a duplex. Bureau of Alcohol, Tobacco, Firearms and Explosives agent Tom Ahern said warrants were being served at the gunman's home. Residents were allowed to return to their homes Monday.

During the chaotic hours after the first shots were fired, police in tactical gear and carrying assault rifles surrounded the temple with armored vehicles and ambulances. Witnesses struggled with unrealized fears that several shooters were holding women and children hostage inside.

The first officer to respond was shot eight to nine times with handgun as the officer tended to a victim outside.

A second officer then exchanged gunfire with the suspect, who was fatally shot. Police had earlier said the officer who was shot killed the suspected shooter.

The wounded officer was in critical condition along with two other victims early Monday, authorities said.

Tactical units went through the temple and found four people dead inside and two outside, in addition to the shooter.

Jatinder Mangat of Racine, a nephew of the temple's president, said when he learned that people had died, "it was like the heart just sat down."

Balginder Khattra of Oak Creek, said Monday that his 84-year-old father, Suveg Singh Khattra, was among the six people police said were killed. Khattra says his father didn't speak English but loved living in America.

Sikhism is a monotheistic faith founded more than 500 years ago in South Asia. It has roughly 27 million followers worldwide. Observant Sikhs do not cut their hair. Male followers often cover their heads with turbans — which are considered sacred — and refrain from shaving their beards. There are roughly 500,000 Sikhs in the U.S., according to estimates. The majority worldwide live in India.

The Sikh Temple of Wisconsin started in 1997 with about 25 families who gathered in community halls in Milwaukee. Construction on the current temple in Oak Creek began in 2006, according to the temple's website.

The New York-based Sikh Coalition has reported more than 700 hate crimes in the U.S. since 9/11 and has fielded complaints in the thousands from Sikhs about workplace discrimination and racial profiling. With their turbans and long beards, Sikhs are often mistaken for Muslims or Arabs, and have inadvertently become targets of anti-Muslim bias in the United States.

The shootings also came two weeks after a gunman killed 12 people at movie theater in Colorado.