D.C. Mayor Vincent Gray's administration says accusations of unethical behavior by the executive director of the D.C. Lottery are "serious."

Buddy Roogow, who has run the lottery since 2009, allegedly forced an aide to assist him with his work in teaching a college course, ordered employees to sell lottery tickets and fired workers to make way for his own appointees.

A "concerned citizen" leveled the allegations in an August 2011 letter to city officials that The Washington Times first reported on Monday.

"Mr. Roogow is not only ethically challenged," the author wrote. "He is also incompetent."

Though the writer sent their concerns to Inspector General Charles Willoughby, the District's internal watchdog has not released a report on his review.

But city officials said an internal review by the office of Chief Financial Officer Natwar Gandhi, who oversees the lottery, found no evidence of wrongdoing, and Gandhi's office said Monday that it retains confidence in Roogow.

"He's doing very well and the finances will show it," Gandhi spokesman David Umansky said.

Pedro Ribeiro, a mayoral spokesman, said Gray expects

the city to resolve the accusations against Roogow.

"These are serious allegations, and the mayor hopes Dr. Gandhi and the inspector general get to the bottom of the matter," Ribeiro said.

The charges against Roogow, whose office did not respond Monday to a request for comment, are the latest stain on the lottery. The Washington Examiner first reported in July that the circumstances surrounding the awarding of the lottery management agreement are the subject of an investigation by a federal grand jury.

The grand jury has issued subpoenas that reference the federal law banning bribery of public officials, but federal prosecutors have declined to comment on the probe.