Federal investigators say they have probable cause to believe that a conspiracy existed to defraud thousands and possibly millions of dollars from the government-backed program that insures crops, according to court records released Monday in Lexington. The alleged conspiracy involved Central Kentucky tobacco farmers, crop insurance agents, crop insurance adjustors, tobacco warehouse owners/employees and others. More than 400 pages of search warrant applications and other documents outlining the alleged conspiracy were released by U.S. District Court.