OAK CREEK, Wisconsin (CNN) -- The man who shot six people to death and wounded three others during a rampage at a Sikh temple in a Milwaukee suburb was an Army veteran who may have been a white supremacist, authorities said Monday.
Law enforcement officials sources familiar with the investigation named him as Wade Michael Page, 40.
Oak Creek Police Chief John Edwards said the attacker shot people inside and outside the temple, including a police officer. Edwards said another police officer with a rifle then shot the gunman, who died at the scene.
According to Edwards, police have received information that the suspect "may have been involved in" the white supremacist movement, but he added it remains unconfirmed. Two neighbors of Page's identified him in a photo that showed him playing in a white-power band called End Apathy, and the nephew of the slain president of the Sikh temple said the attacker had a 9/11 tattoo on his arm.
Earlier, the FBI said that it had not determined a motive for the Sunday morning shooting and that investigators were looking into whether the attack might be classified as domestic terrorism.
Because of their customary beards and turbans, Sikh men are often confused with Muslims, and they have been the targets of hate crimes since the September 11, 2001, attacks on New York and Washington.
Victims of the Sunday morning attack ranged in age from their late 20s to about 70, said Justice Singh Khalsa, who helped translate witness accounts for authorities. Three people remained in critical condition at Froedtert Hospital, the medical center said Monday.
Page, born on Veterans Day in 1971, joined the Army in 1992 and left the service in 1998, according to Army Spokesman George Wright.
According to a Pentagon official, Page was discharged from military service in 1998 for "patterns of misconduct."
One law enforcement official said Page legally owned the gun used in the shooting.
The officials spoke on condition of not being identified because they were not authorized to talk on the record about the shooting investigation.
Edwards said the attacker shot people inside and outside the temple, including a police officer, before another police officer shot him.
"They gave the individual commands. He didn't respond to those," Edwards said "He shot some of the squads, damaging them, and he was at that time shot at by one of our officers with a rifle."
Asked about the officer shot in the attack, Edwards said that "it was very close range."
"He was tending to someone down in a crouch position, what it appears," the police chief said. "And the individual walked up on him, around a vehicle and engaged him very closely - inches to feet, and fired at him. He was shot between eight and nine times."
Edwards said the wounded officer was "resting comfortably with his family and looks like nothing's life threatening at this point."
The suspect had a criminal record, Edwards said. A background check showed Page had separate convictions for DUI in Colorado in 1999 and for criminal mischief in Texas in 1994.
Authorities have not formally released the names of the deceased.
One of the dead was a priest named Prakash Singh, who recently immigrated to the United States with his wife and two young children, said Justice Singh Khalsa, a temple member since the 1990s.
Relatives of Satwant Kaleka, the president of the temple in Oak Creek, Wisconsin, said Monday that he was killed fighting the attacker.
"From what we understand, he basically fought to the very end and suffered gunshot wounds while trying to take down the gunman," said Kanwardeep Singh Kaleka, his nephew.
"He was a protector of his own people, just an incredible individual who showed his love and passion for our people, our faith, to the end," he said, near tears. "He was definitely one of the most dedicated individuals I have ever seen, one of the happiest people in the world."
Kaleka said those inside the gurdwara, or Sikh house of worship, described the attacker as a bald white man, dressed in a white T-shirt and black pants and with the 9/11 tattoo on one arm -- which "implies to me that there's some level of hate crime there."
Tom Ahern, a spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives, said the gunman had a military background but would not elaborate. He also would not elaborate on the man's tattoos.
While officials try to piece together what prompted the man to go on his shooting spree shortly before the main Sunday morning service, America's Sikh community struggled to come to grips Monday with the brutal attack.
Kaleka was horrified to have such violence occur at his place of worship, especially just two weeks after the 12 killings at a screening of the Batman movie "The Dark Knight Rises" in Aurora, Colorado.
"You're talking about Aurora one minute, and the next minute it's you and your family," Kaleka said.
"I just never thought it would be at a temple, at a place of worship. I don't want people to have to carry a gun at a place of worship," said Kaleka, who added that he could have been at the temple during the attack, but for the fact he had stopped at a bank "randomly to make a deposit."
"Why can't people just show each other love and care and treat each other as humans?" he asked.
Khalsa, a temple member since the 1990s, said late Sunday that the attacker was "probably somebody not in their right mind."
"It's possibly a hate crime, somebody not understanding the religion," Khalsa said.
The three people who were wounded remained in critical condition early Monday morning at Milwaukee's Froedtert Hospital. One had been shot in the abdomen and chest, another in the face, and the third in the neck, the hospital said.
Meanwhile in India, the birthplace of Sikhism, Prime Minister Manmohan Singh said he was "shocked and saddened" by the shooting.
"That this senseless act of violence should be targeted at a place of religious worship is particularly painful," Singh, himself a Sikh, said Monday. "India stands in solidarity with all the peace-loving Americans who have condemned this violence."
The country's main Sikh political party, the Shiromani Akali Dal, held a demonstration in New Delhi's embassy district Monday to protest.
"Stop racial attacks on Sikhs," read one of the placards.
In an act of solidarity, U.S. Ambassador Nancy Powell visited a historic Sikh shrine in New Delhi, embassy spokesman Unni Menon said.
Sunday's attack occurred about 10:30 a.m., when temple members were reading scriptures and cooking food in preparation for the main Sunday service and community lunch. The temple has more than 350 members.
According to witnesses, the gunman started shooting in the parking lot, killing at least one person. He then entered the temple and continued firing, they said.
Women who were in the kitchen preparing meals for the congregants "were fortunate enough to basically duck down and dodge" the bullets, said Kanwardeep Singh Kaleka, the temple member.
Some ran to safety outside, others sought refuge in the temple's basement, while many huddled together tightly in the pantry.
A 9 mm semiautomatic pistol believed to have been used by the gunman was found at the scene, a law enforcement source with direct knowledge of the investigation said.
It took several more hours for authorities to thoroughly sweep the building and the surrounding area, checking for clues and signs of additional gunmen, as some witnesses had suspected.
Police spent Sunday night searching the shooter's home in nearby Cudahy, a short distance from the temple.
National and state political leaders, including Gov. Scott Walker, also offered condolences after the killings, which came two weeks after the massacre at a Colorado movie theater that left 12 dead and dozens more wounded.
Presumptive Republican presidential nominee Mitt Romney called the slayings "a senseless act of violence and a tragedy that should never befall any house of worship."
And from the White House, President Barack Obama said the United States had been "enriched" by Sikhs, "who are a part of our broader American family."
"My administration will provide whatever support is necessary to the officials who are responding to this tragic shooting and moving forward with an investigation," he said.
The Sikh religion originated in northern India around 1500 and has about 25 million followers.
The United States is home to about 700,000 Sikhs, nearly all of Indian origin. The men are easily identifiable by their beards and turbans, a tradition that's lasted for 500 years.
But the attire and appearance have also meant that they are often mistaken for Muslims and are targets of anti-Islamic attacks from those who seek to avenge the September 11 attacks.
The first person murdered in retaliation for the 9/11 attacks was a Sikh -- Balbir Singh Sodhi, a gas station owner in Mesa, Arizona. He was shot five times by aircraft mechanic Frank Roque on September 15, 2001. Roque is serving a life sentence.
In the intervening years, the Sikh Coalition, a New York-based advocacy group, reported more than 700 attacks or bias-related incidents.
CNN's Tom Cohen, Brian Todd, Harmeet Shah Singh, Poppy Harlow, Ed Payne, Ted Rowlands, Marlena Baldacci, Matt Smith, Steve Almasy, Greg Botelho, Shawn Nottingham, Carol Cratty, Susan Candiotti and Deborah Feyerick contributed to this report.