PanAm flight PA73 was a scheduled service between Bombay, India and New York-JFK Airport, USA, with intermediate stop at Karachi, Pakistan and Frankfurt, West Germany. During the stopover at Karachi, as passengers boarded the aircraft for the flight, a van that had been modified to look like an airport security vehicle, drove through a security checkpoint up to one of the boarding stairways of the aircraft. Four hijackers stormed up the stairways into the plane, fired shots from an automatic weapon and seized control of the aircraft. Flight attendants were able to alert the cockpit crew using intercom, allowing the pilot, co-pilot and flight engineer to escape through a hatch in the cockpit. During the following 16 hours, Zayd Hassan Safarini, the Jordanian leader of the hijackers, demanded the return of the flight crew to fly the aircraft to Larnaca, Cyprus, where he wanted to secure the release of Palestinian prisoners being detained in Cyprus. During negotiations between Safarini and Pakistani authorities, Safarini threatened to kill all passengers. Four hours into the hijacking, one of the passengers was shot and pushed out the door onto the tarmac below. As nightfall arrived, the hijackers herded the passengers and crew members into the center section of the aircraft. The four hijackers opened fire on the passengers and crew, and threw grenades among them, killing almost 20. Most of the survivors escaped through two doors of the plane which were opened when the firing began. Pakistani special forces commando’s then stormed the plane and arrested the hijackers.