As members of a Wisconsin Sikh community struggle to come to grips with a deadly shooting that left six of their members dead, little is known as to what may have sparked the attack local authorities say the FBI is treating as an act of domestic terrorism. 

Authorities have been silent on what may have caused a still-unidentified gunman to go on the shooting rampage at the Sikh Temple of Wisconsin in the Milwaukee suburb of Oak Creek, killing six and seriously wounding four, including a police officer, before being shot dead.

Late Sunday, the investigation appeared to move beyond the temple as police, federal agents and the county sheriff's bomb squad swarmed a neighborhood in nearby Cudahy. Bureau of Alcohol, Tobacco, Firearms and Explosives agent Tom Ahern said warrants were being served at the home of the shooter.

Prior to starting the search at the 3700 block of Holmes Ave., police asked two blocks of residents to leave the area or remain indoors.