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 use slurs.
The investigative news site The Intercept, citing documents from former contractor Snowden, revealed last week that the agencies had spied on Muslim Americans and that one internal memo used the fictitious name "Mohammed Raghead" as an example of a target.
Sikhs, whose religion requires men to wear turbans, have faced a wave of violence since the September 11 attacks, sometimes by assailants who mistake them for Muslim extremists.
In 2012, a white supremacist shot dead six Sikhs at their temple in Wisconsin. Amardeep Singh, co-founder of the Sikh Coalition, said that the group wanted to assess whether the use of epithets is pervasive among US authorities, and for action to be taken if so.
"We need to have a sense of whether the government agency officials charged with protecting our community from bias and bigotry in the form of hate crimes are in some ways hateful themselves," Singh said.
"I can't imagine what would happen if the FBI or NSA were using epithets against black people or the Jewish community in this day and age. I would expect heads to roll," he said. The White House has said that the use of such slurs is "unacceptable and inconsistent" with US values and ordered a review of standards on tolerance and diversity.