The motive of the Wisconsin shooter has not been identified, but there have reportedly been hundreds of bias attacks against Sikhs since September 11, 2001.
Sikhs are often mistaken for Muslims and the men are easily identified by their long beards and turbans. It's the fifth largest religion in the world, and California is home to nearly half of the entire American population of Sikhs. The first Sikh temple in the U.S. was built in Stockton in 1912.
Recently, the California legislature designated November 2012 as California Sikh Awareness and Appreciation Month.
Madeleine spoke to Gurujodha Singh Khalsa, a Sikh minister in Bakersfield, about how the tragedy affected the local Sikh community.