The Federal Bureau of Investigation is struggling to find enough agents and resources to investigate criminal wrongdoing tied to the country’s economic crisis, according to current and former bureau officials.

The bureau slashed its criminal investigative work force to expand its national security role after the Sept. 11 attacks, shifting more than 1,800 agents, or nearly one-third of all agents in criminal programs, to terrorism and intelligence duties. Current and former officials say the cutbacks have left the bureau seriously exposed in investigating areas like white-collar crime, which has taken on urgent importance in recent weeks because of the nation’s economic woes.