On the morning of 30 January 1987, a coach belonging to Zaragoza General Military Academy set out on its route to pick up different army officers. Shortly after 8.05 am, the vehicle, with twenty occupants on board, pulled onto the roundabout at Plaza César Augusto. At that moment, an ETA unit remotely detonated a device containing 50 kilos of Goma-2 and shrapnel hidden in a van parked in front of the church of San Juan de los Panetes.
Major Manuel Rivera Sánchez and the driver of the minibus, José Ángel Ramos Saavedra, died as a result of the explosion. The effects of the blast were felt within a radius of 800 metres and a further 35 people were injured, including both civilians and soldiers. ETA member Henri Parot was convicted and sentenced to imprisonment as the perpetrator of the attack, and Francisco Múgica Garmendia and José María Arregui Erostarbe were both convicted of aiding and abetting. It was the first fatal attack to be carried out by ETA in Aragon.
Manuel Rivera Sánchez, a major in the army engineers, was married and had three children. At the time of his death, he was working as a teacher in the General Military Academy in Zaragoza. He was severely wounded by the blast and taken to the University Clinical Hospital. He died two hours later, as he was about to undergo surgery.