Guillermo Benavides Moreno began his military career in the air force. As a lieutenant colonel in 1984, he was named commander of the Belloso Battalion and, later, commandant of the Miliary Detachment No.3 in La Unión. In 1987, he was appointed head of the Military Detachment No.5 in Cojutepeque. The following year, he was appointed chief of the Intelligence Union (C-2) of the Joint Military Command. He remained in this post for a year, before being name director of the Military Academy “Captán General Gerardo Barrios” on 1 June 1989.
From 1980 to 1992, El Salvador was divided by an internal armed conflict between the rebel Farabundo Martí National Liberation Front (FMLN) and the Government, led by the Nationalist Republican Alliance (ARENA).
In this context, on 16 November 1989, six Jesuit priests, a cook and her 16 years old daughter were killed at the Pastoral centre of José Simeón Cañas Central American University in San Salvador (UCA). The victims were Fathers Ignacio Ellacuría, Rector of the University; Ignacio Martín-Baró, Vice-Rector; Segundo Montes, Director of the Human Rights Institute; Armando López, Joaquín López y López and Juan Ramón Moreno, all teachers at UCA; and Elba Ramos and her daughter, Celina Ramos.
These murders were investigated by a Truth Commission, established during the Chapultepec Peace Accords in 1992. According to their findings, Colonel René Emilio Ponce gave Colonel Guillermo Alfredo Benavides the order to kill Father Ignacio Ellacuria and any potential witnesses.
On 16 November 1989, a group of soldier from the Atlacatl Battalion entered the Pastoral Centre of the UCA. The soldiers initially tried to force their way into the building, until the priests opened the doors to them, allowing them to enter. The priests were forced to lie face down in the back garden, while the soldiers searched the residence.
The lieutenant Guerra allegedly gave the order to kill the priests. Private Grimaldi allegedly shot and killed Fathers Ellacuria, Martín-Baró and Montes, while Deputy Sergeant Antonio Ramiro Avalos Vargas allegedly killed Fathers López and Moreno.
Subsequently, Father Joaquín López y López was allegedly killed by Pérez Vasquez, while Deputy Sergeant Tomás Zarpate Castillo shot Julia Elba Ramos and her daughter Celina Mariceth Ramos. Private José Alberto Sierra Ascencio returned and shot them both again to make sure they were dead.
Finally, according to the Truth Commission, the soldiers fired a machine gun at the façade of the residence, as well as rockets and grenades. They allegedly left a cardboard indicating “FMLN executed those who informed on it. Victory or death, FMLN.”