WASHINGTON - Three top officials of a nationwide cleaning service were charged Thursday with fraud and tax crimes as part of an ongoing federal investigation that also netted hundreds of illegal immigrants in 18 states.

The illegal immigrants were working as janitors for Nevada-based Rosenbaum-Cunningham International, Inc., or RCI, a cleaning contractor for businesses. The workers were swept up early Thursday in 63 locations nationwide, including restaurants such as the House of Blues, Hard Rock Cafe, ESPN Zone, Planet Hollywood, and others, according to a law enforcement official.

RCI co-owners Richard M. Rosenbaum and Edward Scott Cunningham, and firm controller Christina Flocken, face various criminal fraud, immigration and tax charges in the 23-count indictment unsealed in U.S. District Court in Grand Rapids, Mich.

The investigation, led by U.S. Immigration and Customs Enforcement, began 20 months ago from concerns about cleaning crews at the Grand Traverse Resort in northwestern Michigan.

RCI contracted with the resort between June 1997 and March 2006, according to the indictment. Between 2002 and 2006 alone, Grand Traverse paid RCI over $3 million for grounds and maintenance services, kitchen cleaning and housekeeping duties.

But RCI failed to pay employment taxes on its nationwide operations - defrauding the government of more than $18 million - and did not require its workers to show proof of legal U.S. residence as required by law, according to the indictment.

An estimated 250 illegal immigrants working as janitors were caught up in the probe, according to the law enforcement official, who spoke on condition of anonymity because the charges had not yet been publicly announced.