CHICAGO, Aug. 6 (Xinhua) -- A disturbing portrait of the Wisconsin gunman continued to emerge on Monday, as law enforcement officials tried to find what caused the suspect to shot six people dead and three wounded at a Sikh temple.

The 40-year-old suspect, Wade Michael Page, a U.S. Army veteran and alleged former white supremacist, was shot dead by the police shortly after the Sunday shooting rampage in Oak Creek, Wisconsin.

While Oak Creek Police Chief John Edwards did not give a motive for the shooting, it is being treated as an act of "domestic terrorism."

Local media reports related to the gunmen published a painted picture of someone who was a skinhead or white supremacist and wore a tattoo of a 9/11 memorial on his arm. But criminal justice experts and forensic psychologists said it is too early to determine what caused the gunman to open fire.

"We don't want to blame this shooting on the economy or on veterans because we just don't know anything at this point," Louis B. Schlesinger, professor of forensic psychology at John Jay College of Criminal Justice of the City University of New York, told Xinhua.

"This doesn't happen a lot. We don't know what happened, but it's very infrequent. We do know that the Sikh people look different and that might have angered him because he could have thought they were Muslims. He didn't know that they are pacifists."

Officials at the Southern Poverty Law Center, a nonprofit organization fighting hate and bigotry, said that Page has been on their watch list for about a decade because of his connections to white supremacists.

What is known is that, according to the Southern Poverty Law Center, he played guitar and sang vocals for a band called End Apathy, which has released music on Label56 since its started in 2005. Label56 has been tracked by the Southern Poverty Law Center since 2006 because of its "active promotion and distribution of racist hate music," the group said in a news release.

In an effort to distance itself from the shooting, Label56 released a statement on Monday afternoon.

"We have worked hard over the years to promote a positive image and have posted many articles encouraging people to take a positive path in life," the statement said. "We have never sought attention by using 'shock value' / symbols and ideology that are generally labeled as such. With that being said, all images and products related to End Apathy have been removed from our site."

The Southern Poverty Law Center said in a news release that while the label might have stopped selling End Apathy's albums, it continues to offer such hate rock bands as Stormtroop 16, Children of the Reich, Total War and Bound for Glory.

Schlesinger said that Page's connection to the group is circumstantial evidence and does not count as a clear motive for the shooting. "We have to wait for collective evidence from friends and family, and wait before we can reach any conclusions about what led to the shooting," he said.

The shooting sent shockwaves across the nation because it came on the heels of the Colorado movie theater shooting massacre when a man dressed in black strode through the emergency door and shot and killed 12 people.

The incident also came more than a year after the January 2011 shooting of Arizona Congresswoman Gabriella Giffords. Six people, including a 9-year-old girl, were killed and 12 others were injured after a gunman opened fire at a public gathering outside of a grocery store in Tucson, Ariz.

As for why anyone would commit such a horrific act, it hard to say, according to Tamara Lave, associate professor at the University of Miami School of Law.

"Research shows that mass killers are different than serial killers," she told Xinhua. "Serial killers because it satisfies an urge or desire and they can go for long stretches of time. Mass killers are depressed and anxious and have serious psychological problems. They are usually alienated and loners and depressed. But it's hard to say what set Page off. We just don't know yet." Enditem