The Sikh Coalition filed a request under the Freedom of Information Act seeking all emails since the September 11, 2001 attacks by employees of the FBI and the National Security Agency that contain the anti-Sikh epithets.
"As Americans, we expect law enforcement officials to behave like adults," said Amardeep Singh, programme director of the Sikh Coalition.
Such a move follows after recent news reports that NSA and FBI officials may have used the ethnic slur "raghead" in surveillance programmes targeting American-Muslims.
"The Sikh Coalition will not tolerate the use of racial or religious slurs by people who are supposed to protect us. We therefore demand a full accounting of NSA and FBI emails to determine the extent to which agency employees are combating bigotry, not promoting it," Singh said.
In August 2012, a gunman with known ties to neo-Nazi groups attacked a Gurdwara in Oak Creek, Wisconsin, killing six worshippers and injuring several others, including a local law enforcement officer.
In the months after the massacre, a Sikh business owner was shot and injured in Port Orange, Florida; a Sikh octogenarian was beaten with a steel rod in Fresno, California; and a Sikh professor was assaulted in New York City.
Given the persistence of hate violence against Sikh Americans, and after a lengthy campaign by the Sikh Coalition, civil rights groups, and numerous members of Congress, the FBI finally agreed in 2013 to begin tracking hate crimes against Sikhs, it said.
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