Wade Michael Page, 41, the army veteran who was killed Sunday after gunning down the six people at the gurdwara, left behind a startling trail of clues detailing his descent into hate in the tattoos that marked his body and in his music.
Many of the tattoos covering his arms and torso, Marilyn Mayo, co-director of the Anti-Defamation League's Centre on Extremism, said contained specific racist codes and hidden symbols that showed his allegiance to white supremacist beliefs and to a specific skinhead group.
The ADL maintains an on-line database of racist symbols.
"Symbols are an important part of this culture," Mayo said.
"It allows others to know you're part of the skinhead movement and is used as a way of intimidation. Getting a tattoo is permanent and it comes with a serious commitment. It means you're a member, you're part of this club and have been initiated," he said.
Page, 41, had a tattoo on his right arm below his shoulder with the number '838', which Mayo said is a coded symbol indicating membership in the Hammerskins, a skinhead group whose members have been accused of multiple violent crimes, including murders, since the 1980s.
The number '838' corresponds to the letters HCH, an acronym for the group's motto 'Hail the Crossed Hammers', a reference to the group's logo, ABC News reported.
"The tattoo is indicative of membership in the Hammerskins," Mayo said. "Only a member would have that tattoo."
The ADL believes that he was a prospective member as recently as early 2011, but that his membership became official in late 2011.
A former soldier, Page was demoted from sergeant to specialist before leaving the army in 1998. His body art would have been banned under army policies outlawing extremist and racist tattoos.
In the years following his discharge, Page posted dozens of photos of himself on-line that show the ink on his body.
On the back of his hands, he had tattooed the letters 'W' and 'P', which Mayo said is an acronym for White Power.
On his left shoulder appeared a Celtic cross, a cross inscribed inside a circle.
"The Celtic cross is a symbol of white pride and is one of most popular symbols for neo-Nazis and White Supremacists," Mayo said.
Within the circle on Page's arm was the number 14, which corresponds to the number of words in the supremacist motto: 'We must secure the existence of our people and a future for white children'.