Wade Michael Page, 40, is seen in this undated picture from a myspace.com web page for the musical group "End Apathy". Page has been identified by law enforcement officials as the gunman who shot dead six people and seriously wounded three, including a police officer, at the Sikh Temple of Wisconsin on Sunday as worshippers prepared for religious services. REUTERS/myspace.com/Handout

Oak Creek, Wisconsin - US federal agents believe the slain suspect in a deadly attack on worshippers at a Sikh temple in Wisconsin had ties to white supremacist groups, a senior investigator said Monday.

Special Agent Teresa Carlson, head of the Federal Bureau of Investigation's Milwaukee field office, confirmed that 40-year-old suspect Wade Michael Page is the subject of a “domestic terrorism” probe following Sunday's massacre.

“We are looking at ties to white supremacist groups,” Carlson told a news conference on the day after Sunday's shooting, in which six people attending a service at a suburban Sikh temple were shot dead.

“We did not have an active investigation on him before yesterday,” she said. “No law enforcement agency had any reason to believe he was plotting anything.

“We are working on it as a possible domestic terrorism case,” she added. “The definition of domestic terrorism is the use of violence for social or political gain. That's obviously what we are looking at.”

Carlson said the FBI was always on the alert for possible copy cat attacks after such an incident, but noted that investigators had no specific evidence to fear that any further violence is being planned.

She said that the firearm retrieved at the scene of the shooting was a 9mm handgun that had been purchased legally and that the shooter had had several magazines with which to reload the weapon.

Officers had searched his home, which was not booby-trapped. Investigators released a picture of the suspect and urged members of the public with any information on him to come forward.

“We don't have any reason to believe there was anyone else associated with this shooting,” Carlson said. “We are continuing to work and if there is anybody we will identify them” - Sapa-AFP