and there was no way to know if the bomb was truly disarmed or safe to move. The FBI decided that the bomb would have to be disarmed in the hotel. All guests and staff were evacuated from the hotel and the gas main was shut off. After studying the bomb for more than a day through x-rays, bomb technicians decided that, although there were warnings from the bomb maker that a shock would trigger the device, the best hope of disarming it was by separating the detonators from the dynamite. The technicians thought this could be accomplished using a shaped charge of C-4. The attempt to disarm the bomb failed as the technicians did not know that dynamite had also been placed in the top box containing the detonation circuit; the shaped charge detonated the top box explosives, which caused the rest of the bomb to detonate. The bomb destroyed much of the hotel, although no one was injured. The explosion also damaged Harrah's Casino (connected to Harvey's Resort via a tunnel), breaking many of the casino's windows. The bomb, one of the largest the FBI had ever seen, was loaded with an estimated of dynamite stolen from a construction site in Fresno, California. According to FBI experts, the Harvey's bomb remains the most complex improvised explosive device they have examined, and a replica of "the machine", as the extortionists called it, was still used in FBI training . Investigation The bomb was delivered to the casino's second floor by two men posing as technicians; witnesses spotted a white van marked with "IBM" on the side. Birges was investigated as a possible suspect due to his white van being identified as being in South Tahoe at the time of the bombing. Birges was eventually arrested based on a tip. One of his sons had revealed to his then-girlfriend that his father had placed a bomb in Harvey's. After the two broke up, she was on a date with another man when they heard about a reward for information, and she informed her new boyfriend about Birges. This man then called the FBI. John Birges' two sons both entered pleas of guilty in 1981 for their roles in the bombing, serving no prison time in exchange for testifying against their father. Birges was convicted in 1982 and sentenced to life in prison without parole. Birges' two accomplices who delivered the