A black supervisor at the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) is suing the federal government after she claimed she was harassed, held back and discriminated against for complaining about a white supervisor with a Nazi tattoo on his arm who allegedly also sent emails from his work account mocking minorities and then-President Obama.

Cheryl Bishop complained the agency squashed a prestigious assignment she had in Washington, D.C., after she complained about her supervisor Bradford Devlin in 2016.

Bishop filed the lawsuit in 2018 but it recently gained momentum after U.S. District Judge Thomas Zilly denied a government motion to dismiss the case. Zilly also brushed aside hundreds of pages of briefs filed by the government seeking a summary judgment in the case as well as a request to postpone the case, The Seattle Times reported.

Instead, Zilly ordered attorneys to be ready for trial on Oct. 28.

Bishop, a senior supervisory agent and a former bomb-dog handler, worked as a member of the agency's Special Response Team. In her lawsuit, she claims the Bureau of Alcohol, Tobacco Firearms and Explosives abruptly decided she could no longer be a canine handler if she took a one-year assignment to work in the bureau's Science and Technology division in D.C. after telling her previously she could do both. Bishop said the new stipulation only came after she filed a complaint against Devlin for racial harassment.

Devlin, now a senior supervisor in the Seattle Field Divison of the ATF, sports a large tattoo on his left shoulder of an eagle and shield bearing two lightning bolts — a stylized "SS." In a deposition, he acknowledged the tattoo references "Schutzstaffel," Adolf Hitler's infamous secret police squad responsible for murdering millions of Jews and other minorities during World War II. Devlin has worn his Nazi-themed tattoo for nearly two decades. He said he got it while working undercover with "The Order of Blood," an outlaw white supremacist biker gang in Ohio and refuses to remove it, calling it a "war trophy" from his undercover days.

Bishop found out about the tattoo in 2009 when she was assigned to a group Devlin supervised. She said Devlin rolled up his sleeve and showed off the arm ink during a retirement party for an agent in 2011 "while eyeing (Bishop) with a grin." Bishop said she complained to another supervisor but that nothing was done. Bishop also filed a formal complaint with the Equal Employment Opportunity Commission in May 2016 and claimed Devlin bad-mouthed her to federal prosecutors and law enforcement officials in Oregon after she was tapped to temporarily replace him.

Devlin also allegedly sent a series of emails from his work account that were racially insensitive. After the agency learned in 2016 that Devlin still had the Nazi tattoo and was posing proudly in pictures with it, they pulled a pending promotion to the agency's Internal Affairs Division. As a result, Devlin sent a letter to the ATF claiming he was being discriminated against because as a white man he expressed his doubt about the qualifications of Bishop, a black woman.

In an emailed statement to Fox News on Monday, April Langwell, the chief of the agency's public affairs division, said the bureau takes allegations of misconduct - on or off duty- seriously. She added that any form of racism at the agency would not be tolerated.