A man suspected of killing six people at a Sikh temple in Oak Creek Wisconsin at the weekend was said to be a 40-year-old army veteran and "frustrated neonazi."
Officials and witnesses said a gunman walked into the Sikh Temple of Wisconsin and opened fire as several dozen people prepared for Sunday morning services.
First Assistant US Attorney Greg Haanstad in Milwaukee named the suspect as Wade Michael Page and a US defence official who spoke on condition of anonymity said Mr Page joined the army in 1992 and was discharged in 1998.
Civil rights organisation the Southern Poverty Law Centre claimed that Mr Page was a "frustrated neonazi" who led a racist white supremacist band End Apathy.
Police called Sunday's attack an act of domestic terrorism.