A veteran auditor for the Minnesota Department of Revenue is suing the state, alleging that he was subjected to "unfair and discriminatory treatment" because of his race and national origin.

Diaib Richard Sopelle, a native of Ghana and an American citizen, started his career with the state's tax collector in 2005. He says in the lawsuit filed this week in Ramsey County that despite significant expertise — including a Ph.D. in financial accounting — he was blocked from promotions that were earned by less qualified white colleagues, even though, in some cases, Sopelle had trained them.

"Dr. Sopelle is not asking for affirmative action. What we're asking for is the process to be fair," said Kenneth Udoibok, a Minneapolis civil rights attorney.

Ryan Brown, a spokesman for the Department of Revenue, released a statement to the Star Tribune saying the agency does not comment on pending litigation, adding, "We take any allegation of discrimination seriously, because we are committed to the implementation of the affirmative action policies, programs and procedures that ensure our employment practices are free from discrimination."

The statement continued: "We are committed to an inclusive work environment that recognizes, accepts and incorporates our diversity and reflects the communities we serve."

The lawsuit comes as former Gov. Mark Dayton and new Gov. Tim Walz, both Democrats, have touted their administrations' inclusiveness in the midst of diversifying demographics of both the DFL Party and Minnesota more broadly.

Sopelle's court filing asserts that "subjective hiring and promotion processes have caused an adverse impact" on black workers because they are repeatedly passed over for advancement. The agency has only one black supervisor in the division Sopelle works in, sales and use taxes, according to the lawsuit.

Sopelle's attorney Udoibok said superiors at the Revenue Department choose applicants for jobs and promotions based on "affinity, which is another way of saying they are more comfortable with the applicant, and because there are more whites in management, more Caucasians get the jobs and African-Americans don't, and that's how you see the disparity. I think it's unlawful."

According to the lawsuit, Sopelle frequently was forced to overcome artificial barriers to advancement, constructed to impede him for no known reason. The lawsuit asserts the only possible reason is his race.

He was warned by a co-worker after taking the job that his first supervisor would be biased against him because of his race.

He was falsely accused of stealing a co-worker's computer bag. He was once transferred so another worker, whom Sopelle had trained in auditing work, could be promoted above him, according to the lawsuit. His work was subjected to more scrutiny than that of his white colleagues, the filing alleges. His attempts at advancement were repeatedly thwarted while white workers, some with just a high school degree, were promoted above him.

Cynthia Bauerly, the department commissioner, and Lee Ho, the deputy commissioner, are named as defendants in their official capacities.

J. Patrick Coolican • 651-925-5042