A 40-year-old US army veteran has been identified as the gunman who killed six worshippers at a Sikh temple in Wisconsin, authorities said.
The assailant, shot dead by police at the scene on Sunday, was on Monday identified as Wade Michael Page and authorities were investigating possible links to white supremacist groups and his membership in skinhead rock bands.
Page served as a soldier in the army from 1992 to 1998, said police chief John Edwards in the Milwaukee suburb of Oak Creek where the 400-member temple is located.
A day after his attack on the suburban Milwaukee temple, fragments of Page's life emerged in public records and interviews.
But so far, his motive remained largely a mystery and police suggested investigators might never know why he targeted a temple full of strangers.
"We have a lot of information to decipher, to put it all together before we can positively tell you what that motive is - if we can determine that,'' Edwards said.
US media outlets and officials, speaking on the basis of anonymity, said on Monday that Page had links to racist groups in the US.
Bernard Zapor, special agent in charge of the Bureau of Alcohol, Tobacco, Firearms and Explosives, said the 9mm handgun used in the attack was purchased legally and had multiple ammunition magazines.
Page's six-year tenure as a psychological operations specialist and Hawk Missile System repairman in the US military, came to an end in 1998 for "patterns of misconduct", including being drunk while on duty. "He had a general discharge and that he was ineligible for re-enlistment," Edwards said.
Page had been a member of the racist skinhead band End Apathy, based in Fayetteville, North Carolina, in 2010, said Heidi Beirich, director of the intelligence project at the Southern Poverty Law Centre in Montgomery, Alabama.
"That's all we know about Wade. We are still digging through our files," she said.
Police searched Page's apartment on Monday looking for clues to his motive. Authorities are treating the shooting as a case of "domestic terrorism".
Based on Federal Bureau of Investigation guidelines, cases designated as domestic terrorism involve political agendas.
The FBI defines terrorism as “the unlawful use of force or violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives”.
Protests were held in reaction to the attack in the Indian cities of Amritsar and Hyderabad on Monday.
Al Jazeera's Scott Heidler, reporting from Oak Creek, said though there was only one suspect in the shooting itself, police are looking to identify and question a "person of interest" who they said arrived at the temple soon after the shooting and appeared to be "suspicious".
Police were called to the Sikh Temple of Wisconsin in the suburb of Oak Creek, where witnesses said several dozen people were gathering for a service on Sunday.
Authorities found four people dead inside the temple and two outside, Bradley Wentlandt, police chief of nearby Greenfield, said.
Sunny Singh, 21, of Milwaukee, said a friend pulled into the temple's parking lot, heard shots and saw two people fall down.
The friend then saw the shooter reload his weapons and head to the temple's entrance, Singh said.
The first police officer to arrive at the temple engaged in gunfire outside the building with a man police believe was the shooter.
Tactical units went through the temple, and authorities do not believe a second shooter was involved.
Two of the victims were believed to be the president of the congregation and a priest, Lakhwinder Singh, a member of the congregation, said.
"It will take a long time to heal. We're hurt very badly."
It an impromptu vigil in downtown Milwaukee, people gathered in a park and held candles. Sikhs were joined by other members of the community.
Protests in India
Protests were also held in the Indian cities of Amritsar and Hyderabad on Monday.
There are an estimated 2,500 to 3,000 families of the Sikh religion in the Milwaukee area and two temples.
Sikhism is a monotheistic faith that was founded in South Asia more than 500 years ago. 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 US, according to estimates. The majority worldwide live in India.
Speaking to Al Jazeera, Rajdeep Singh, policy adviser for the US-based Sikh Coalition, said that Sikhs in the US have been subjected to “hate crimes and other forms of discrimination” since the 9/11 attacks.
“Unfortunately the prevailing stereotype these days is that if somebody wears a turban they’re somehow associated with extremism," Singh said.