Since 1973, Clelia incorporated many workers of the factory "Cinturón Obrero" of San Salvador, in the secret worker unit of the ERP. She joined the urban guerrilla and took part in armed actions and revolutionary propaganda. In January 1974, aged 19, she went underground to avoid persecutions and joined the armed struggle, where she partecipe to the construction of the Partido de la Revolución Salvadoreña (PRS-ERP - Salvadoran Revolution Party,[5] one of the founding subjects of the FMLN)[6] becoming a member of its central committee in 1977. As member of it, she was responsible for the party and participated in the preparation of the general offensive of 1981 around the city of San Salvador, when she was captured of February 11.
For 22 days Clelia stayed on condition of desaparecida in a clandestine prison of the Policía Nacional (National Police), wheres she was found by the International Red Cross and transferred to the women's prison of Ilopango. She was released in June 1983 by an amnesty decreed by the government of Álvaro Magaña. After it, she joined the north-eastern military front Francisco Sánchez of the FMLN. Two months later she died in battle.
In a 1992 song of the Italian group Banda Bassotti, named Figli della stessa rabbia, the Commander Clelia was cited with other revolutionary marxists.[10] The song is part of the homonym album[11]
