Updated 6:18 p.m. ET
(CBS/AP) OAK CREEK, Wis. - Before he strode into a Sikh temple with a 9 mm handgun and multiple magazines of ammunition, Wade Michael Page played in white supremacist heavy metal bands with names such as Definite Hate and End Apathy.
The bald, heavily tattooed bassist was a 40-year-old Army veteran who trained in psychological warfare before he was demoted and discharged more than a decade ago.
When the shooting at the Sikh Temple of Wisconsin in suburban Milwaukee ended, six victims ranging in age from 39 to 84 years old lay dead. Three others were critically wounded, including Oak Creek Police Officer Lt. Brian Murphy.
Page was shot and killed by 32-year Oak Creek Police veteran Sam Lenda on scene.
A day after the shooting, fragments of Page's life emerged in public records and interviews. But his motive was still largely a mystery. He left no hate-filled manifesto, no angry blog or ranting Facebook entries to explain the attack.
Page joined the Army in 1992 and was discharged in 1998. He was described Monday by the Southern Poverty Law Center as a "frustrated neo-Nazi" who had long been active in the obscure underworld of white supremacist music.
Mark Potok, a senior fellow at the nonprofit civil rights organization in Montgomery, Ala., said Page played in groups whose sometimes sinister-sounding names seemed to "reflect what he went out and actually did." The music often talked about genocide against Jews and other minorities.
In a 2010 interview, Page told a white supremacist website that he became active in white-power music 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.
End Apathy's MySpace page said the group was based in Nashville, N.C.
Joseph Rackley, who lives in Nashville, said Monday that Page lived with his son for about six months last year in a house on Rackley's property.
"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 assigned to a battalion at Fort Bragg, N.C.
As a "psy-ops" specialist, Page would have trained to host public meetings between locals and American forces, use leaflet campaigns in a conflict zone or use loudspeakers to communicate with enemy soldiers.
He never deployed overseas while serving in that role, Pentagon spokesman George Wright said.
Page was demoted in June 1998 for getting drunk while on duty and going AWOL, two defense officials said, speaking on condition of anonymity because they were not authorized to release information about the gunman.
Page also received extra duty and was fined. The defense officials said they had no other details about the incident, such as how long Page was gone or whether he turned himself in.
Outside Fayetteville, N.C., a brick ranch house Page bought in 2007 with help from a Veterans Administration mortgage stood boarded up Monday with knee-high weeds in the yard. A notice taped to the front indicated the home was in foreclosure and had been sold to a bank in January.
Before buying the home, Page lived with Army soldier Darren Sherlock, his wife and young children in a doublewide trailer in a rural community near Fort Bragg, records show.
Sherlock, dressed in his military fatigues, declined to comment about Page or the shooting when approached Monday by The Associated Press.
Back in Wisconsin, Page responded to a recent online ad seeking a roommate in Cudahy, a small city outside Milwaukee.
Kurt Weins, who placed the ad, said Page moved in June 23 with only a television set, telling him he had recently broken up with his girlfriend and needed a place to stay.
"We talked, but it was really about nothing," Weins said. "He seemed pretty calm. He didn't seem like the type to raise his voice."
On July 15, Page moved to a duplex across the street. After the FBI searched that residence Sunday, Weins said he returned to the apartment and found only a computer desk, chair and an inflatable mattress.
Peter Hoyt, who lives about a block from Page's last apartment, said he spoke with Page about a dozen times. Hoyt remembered Page having a "9/11" tattoo on his arm but could not describe it.
"I never heard the guy ... say anything negative," Hoyt said. "When I found out it was him, I was awed. I can't believe it was him."
Online records show Page had a brief criminal history in other states, including pleading guilty to misdemeanor criminal mischief after a 1994 arrest in El Paso. He received six months' probation. Page also pleaded guilty to driving under the influence in Colorado in 1999 but never completed a sentence that included alcohol treatment, records show.
Suburban Milwaukee police had no contact with Page before Sunday, and his record gave no indication he was capable of such intense violence.
The FBI was leading the investigation because the shooting was considered domestic terrorism. The agency said it had no reason to believe anyone other than Page was involved.
Other sources tell CBS News correspondent Bob Orr it may be more accurate to refer to "an investigation into a possible hate crime."
Page entered the temple as several dozen people prepared for Sunday services. He opened fire without saying a word.
The president of the temple died defending the house of worship he founded.
Satwant Singh Kaleka, 65, managed to find a simple butter knife in the temple and stab the gunman before being shot twice, his son said Monday.
Amardeep Singh Kaleka said FBI agents hugged him, shook his hand and told him his father was a hero.
"Whatever time he spent in that struggle gave the women time to get cover" in the kitchen, Kaleka said.
The bodies of the victims are with the Milwaukee County Medical Examiner, reports CBS Affiliate WDJT. Autopsies will be performed today.
Federal officials said the gun used in the attack had been legally purchased.
Page was issued five pistol-purchase permits in 2008 in North Carolina, paying a $5 fee for each. The Cumberland County Sheriff's office declined to release his application form, which requires another person to affirm the applicant is of "good moral character." The forms also typically ask about military experience of applicants, who must pass a criminal background check.
Page did not have the additional permit needed to legally carry a concealed weapon.
On Sunday, the first officer to respond was shot eight to nine times as he tended to a victim outside. A second officer then exchanged gunfire with the suspect, who was fatally shot.
The six dead ranged in age from 39 to 84 years old. Three people were critically wounded, including the police officer.
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 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.
Sunday's shooting came two weeks after a gunman killed 12 people at movie theater in Colorado.