Bomb threats prompted evacuations and police searches of three Connecticut courthouses on Friday morning. Authorities said a local TV station and a State Police dispatcher received similar calls warning of bombs at state superior courts in Hartford, New Haven, and Waterbury. The threats were made at about 8 a.m., before the courthouses opened. Police bomb squads searched the three buildings and did not find anything. State Police Lieutenant J. Paul Vance said detectives have begun a criminal investigation.