At 6:55 pm on 26 May 1979, a powerful explosion went off in the California 47 café, situated at 47 Calle Goya, Madrid. The device, made up of between four and five kilograms of explosives, had been placed in the ground-floor toilets. Eight people were killed by the blast, most of them elderly women and around another fifty people were injured. The premises was almost completely destroyed by the force of the explosion. The attack was blamed on GRAPO. The café was near the headquarters of New Force (Fuerza Nueva, a far-right political party) and was frequented by sympathisers of the organisation.
María Teresa Alonso de Celis (45) was the daughter of Octaviano Alonso de Celis, who for many years had been the deputy mayor of Madrid, president of the Club de Campo and honorary consul of Costa Rica in Spain. She was buried on 28 May 1979 in Madrid accompanied by a funeral cortege of 200 people, including the parliamentarian and president of Fuerza Nueva, Blas Piñar.