Bret Caldwell, a spokesman for the International Brotherhood of Teamsters, said Local 120 was placed into emergency trusteeship after a "determination that there has been a violation of fiduciary responsibility," the Minneapolis Star Tribune reported.
Caldwell told the newspaper the local's top officials, Brad Slawson Sr. and Brad Slawson Jr., were placed on a leave of absence and its executive leadership board was dissolved.
Local 120, based in Blaine, Minn., has about 10,000 members in Minnesota, Iowa, North Dakota and South Dakota.
Hoffa said in a memo posted on the local's office doors that "concerns" had been raised about the local's purchase of real estate for, and construction of, a new union hall in 2007 and 2008.
Among the alleged irregularities were the payment of a $90,000 "finder's fee" by the building's general contractor to a close family friend of a union leader and an unauthorized allocation of $189,000 from the local's strike fund to pay for the new building.
Irregularities also were found at a bar and gaming operation in Fargo, N.D., known as the "Teamsters Club," where a close friend of the Slawsons was said to be employed as a consultant without executive board approval.
The newspaper said the Slawsons could not be reached for comment.