Soldier. Singer. Skinhead.

Investigators spent Monday trying to figure out what led 40-year-old Wade Michael Page from repairing missiles for the Army to a Sikh temple in suburban Milwaukee, where he was killed by police at the end of a Sunday morning rampage.

The shaven-headed Page, whose tattoos included the Celtic cross adopted by white supremacist groups, had been the front man for a white-power rock band called "End Apathy" for several years. Two former neighbors identified him from photos on the band's MySpace page.

His path appears to have taken him from Colorado to Milwaukee, where he enlisted in the Army in 1992; back to Colorado; to North Carolina, where he started the band; and then back to the Milwaukee area, where he had been "a short time" before the shootings, Oak Creek Police Chief John Edwards told reporters Monday.

The Army trained Page first as a mechanic for the Hawk anti-aircraft missile system, then as a psychological warfare specialist. He rose to the rank of sergeant before losing a stripe due to "patterns of misconduct," according to a Pentagon official who spoke on condition of anonymity. In October 1998, he received a general discharge under honorable conditions, the official said.

Christopher Robillard of Oregon, who described Page as "my closest friend" in the service more than a decade ago, said Page was pushed out of the military for showing up to formation drunk.

He described Page as "a very kind, very smart individual -- loved his friends. One of those guys with a soft spot." But even then, Page "was involved with white supremacy," Robillard said.

"He would talk about the racial holy war, like he wanted it to come," Robillard said. "But to me, he didn't seem like the type of person to go out and hurt people."

Later Monday, Robillard told CNN's "Piers Morgan Tonight" that Page likely sought attention to his beliefs "because he was always the loner type of person. Even in a group of people, he would be off alone."

Teresa Carlson, the special agent in charge of the FBI's Milwaukee office, said investigators have been told Page may have been involved with the white supremacist movement, but that hadn't been confirmed. No motive for Sunday's attack had been established, but the FBI was investigating whether the killings at the Sikh temple were an act of domestic terrorism, she said.

Page moved back to Denver after his discharge, where he had a tough time in civilian life "and was basically living on the street," Robillard said. It was during that period that Page joined a "racist band" and started to get his body inked, his Army buddy told CNN.

"I asked him why he was aligning himself with this stuff," Robillard said. "He really didn't answer. He would duck it."

Page had a girlfriend who left him for another member of the band, which then kicked him out, Robillard said. The last time they saw each other -- more than 10 years ago -- Robillard said Page was on a motorcycle trip across the country.

It was a trip Page recounted in 2010, in an online interview about his band End Apathy. He founded it in in the small town of Nashville in eastern North Carolina, where he ended up after bouncing around the country from California to West Virginia.

"I am originally from Colorado and had always been independent, but back in 2000 I set out to get involved and wanted to basically start over," he said.

The band put out at least two recordings through a label that promoted them on the neo-Nazi website Stormfront. In a 2010 interview posted online, Page said his lyrics "vary from sociological issues, religion, and how the value of human life has been degraded by being submissive to tyranny and hypocrisy that we are subjugated to."

End Apathy played gigs in North Carolina and in the Midwest, he said. While Page shared the stage with many similar bands, he wasn't a movement leader and doesn't appear to have been involved in any criminal acts, said Mark Potok, who tracks hate groups for the Southern Poverty Law Center in Alabama.

Nevertheless, Potok called Page "a neo-Nazi skinhead in the very thick of the white supremacist movement."

In a statement posted on its website Monday, the band's imprint, Label 56, said it had removed "all images and products related to End Apathy."

"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, to abstain from drugs, alcohol, and just general behavior that can affect ones life negatively," the company said.