DENVER (AP) — The U.S. attorney for Utah has been assigned to investigate a man accused of misrepresenting himself as a lawyer in federal courts.

The Denver Post has reported that Howard O. Kieffer is not a licensed attorney in any U.S. state or territory and did not attend the Antioch School of Law in Washington, D.C., as he claimed in applying to practice in federal court.

Federal prosecutors in Colorado recused themselves from investigating Kieffer because they witnessed him in U.S. District Court in Denver as he represented Gwen Bergman, who was convicted in May of trying to hire a hit man on the Internet to kill her son's father.

Bergman's current attorney, EJ Hurst II, did not return phone messages asking whether he would ask for a mistrial.

Federal court records show Kieffer has represented at least 16 clients in 10 federal courts throughout the country, The Denver Post reported.

Kieffer was able to practice, in some cases because jurisdictions only required a local attorney to vouch for his credentials. In other courts, clerks did not verify whether Kieffer was licensed to practice law in the state he listed on his application.

Kieffer missed a deadline Thursday to provide proof of his bar membership to the 9th Circuit Court of Appeals.