The ERP publicly remained in the forefront. ERP guerrilla activity took the form of attacks on military outposts, police stations and convoys. In 1971, 57 policemen were killed fighting the left-wing guerrillas, and in 1972 another 38 policemen lost their lives in the guerrilla violence. On 28 December 1972, Marine Private Julio César Provenzano of the ERP, is killed when the bomb he planted in one of the lavatories of the Argentine Naval Headquarters went off prematurely. On 3 April 1973, ERP guerrillas kidnapped Rear-Admiral Francisco Agustín Alemán.