 Gorriarán Merlo moved to Nicaragua to collaborate with the Sandinistas, and in 1980 he was involved in the assassination of the deposed Nicaraguan President, Anastasio Somoza Debayle, who was living in exile in Asunción, Paraguay.In the last years of his life he was prohibited entry into Nicaragua, but enjoyed the support and friendship of the Sandinista leader Daniel Ortega.In 1985, Gorriarán Merlo founded the Movimiento Todos por la Patria (MTP).