Federal officials said the gun used to kill six people at a Sikh temple in Wisconsin was bought legally and they have no reason to believe anyone but the slain gunman was involved in the shooting.

FBI Special Agent in Charge Teresa Carlson said Monday that officials aren't aware of more threats to the Sikh Temple of Wisconsin in the Milwaukee suburb of Oak Creek.

She said the FBI is investigating the Sunday shooting as a possible act of domestic terrorism but doesn't know a motive at this time. The Southern Poverty Law Center civil rights group has identified gunman Wade Michael Page, 40, as a known white supremacist.

A senior fellow at the Southern Poverty Law Center told CBS News that Page was a member of several white supremacist rock bands and the music often referred to genocide against Jews and minorities.

ATF Special Agent in Charge Bernard Zapor said Page used a legally purchased 9mm handgun and multiple ammunition magazines in the shooting.

Page, a Colorado native, lived in North Carolina from 2007 to 2011. He was a U.S. Army veteran.

Police said local Wisconsin authorities had no contact with Page before the attack.

Oak Creek Police Chief John Edwards said Monday that authorities in suburban Milwaukee didn't have any run-ins with Page before Sunday's shootings. The shootings ended when Page was fatally shot by police.

Carlson also said the agency isn't aware of any past threats made against the temple. Carlson said the agency had no reason to believe he was planning or capable of such violence.

Authorities said Page entered the Sikh Temple of Wisconsin about 10:30 a.m. Sunday and opened fire.

Oak Creek police Lt. Brian Murphy was shot eight times as he responded.

"Our first officer on the scene, as he entered into the driveway area, he came upon a victim in the parking lot and exited his vehicle and went to assist that individual. It was at that point where he was met by the suspect, who basically ambushed him," Edwards said.

Murphy, a veteran 51-year-old officer, waved off colleagues who tried to come to his aid outside the temple, telling them instead to go tend to the victims who had been shot inside, according to Edwards.

Murphy is a 20-year veteran who Edwards said was a tactical team leader for years.

Police said the second officer to arrive at the scene shot and killed the suspect. The Oak Creek police officer who killed the shooter has been identified as 32-year veteran Sam Lenda.

Wisconsin Professional Police Association Executive Director Jim Palmer said Lenda does not consider himself a hero and was only doing his job. The WPPA is representing Lenda in the police department's internal investigation.

Police said Page killed four people inside the temple and two outside before Lenda shot him outside.

"There's no doubt in my mind that the heroic actions of our police officers prevented an even greater tragedy, and they should be commended for that," said Mayor Steve Scaffidi.

The six people killed by the gunman ranged in age from 39 to 84.

The six victims of Sunday's attack were identified by police as five men -- Sita Singh, 41; Ranjit Singh, 49; Satwant Singh Kaleka, 65; Prakash Singh, 39, and Suveg Singh Khattra, 84 -- and one woman, 41-year-old Paramjit Kaur.

Balginder Khattra, of Oak Creek, said the oldest victim was his 84-year-old father, Suveg Singh Khattra. The younger Khattra said his father moved to Wisconsin in 2004 and loved living in America.

The Sikh community, and the entire community of Oak Creek, is trying to start the healing process after the tragedy.

"It's not easy. It's very hard to accept, but I think religion will help us cope with this problem," said Kulwant Singh Daliwa, a Sikh temple representative.

"Sunday was a tragic day for our city, especially given the fact that it occurred in a place of worship," Scaffidi said.