OAK CREEK, Wisconsin: The gunman who killed six worshippers at a Sikh temple in the US played in white supremacist heavy metal bands and posted frequent comments on Internet forums for skinheads, repeatedly urging members to act more decisively to support their cause.

"If you are wanting to meet people, get involved and become active," Wade Michael Page wrote last year.

"Stop hiding behind the computer or making excuses."

After Page strode into a Sikh temple on Sunday with a 9mm handgun and multiple magazines of ammunition, authorities were trying to determine if the 40-year-old army veteran was taking his own advice when he opened fire on strangers.

Page, who was shot dead by police, described himself as a member of the "Hammerskins Nation", a skinhead group rooted in Texas that has branches in Australia and Canada, according to the SITE Monitoring Service, a private intelligence firm that searches the Internet for extremist activity.