Zvonko Bušić had been the object of suspicion of many of those who looked into the La Guardia bombing which happened on December 29 1975. The suspicion was raised by Lt. McTigue, Edwin T. Dreher, who, as a deputy police chief at the time, was put in charge of solving this case, Frank McDarby, a detective who interrogated Zvonko Bušić in an F.B.I. office 33 years ago; the crime writer Kevin F. McMurray, who spoke with Zvonko Bušić for three hours in 1997 in a visitors’ room at the federal penitentiary in Lewisburg, Pa.; and Robert K. Tanenbaum, a former prosecutor from the Manhattan district attorney’s office. Each of them reviewed this case anew and wondered anew if Zvonko Bušić escaped punishment for one of the biggest unsolved terrorist acts in the USA. Zvonko Bušić denied any involvement in the La Guardia bombing. But Lt. McTigue was struck by the similarities in the two bombings: