Segundo Guillermo Sandoval Puga died that day at 12:30 hours, on Camino La Pirámide, on the slopes of Cerro San Cristóbal, due to gunshot wounds: one to the cranium without an exit wound and another to the abdomen with an exit wound, as recorded in the Medical Death Certificate from the Legal Medical Institute.

Witnesses stated that he was detained on February 26, 1974, around 21:00 hours, by soldiers from the Buin Regiment, while he was with some friends at a soda fountain located in the vicinity of the military unit. According to the witnesses, Segundo Sandoval had a political argument with some soldiers he knew, as he had completed his military service at that same regiment a short time before.

His arrest was denied to his family members. On March 14, 1974, officers from the Investigations Police arrived at the family's home to communicate that the lifeless body of Segundo Sandoval had been found in the La Pirámide sector with two gunshot wounds.

Considering the background information gathered and the investigation conducted, the Superior Council of this Corporation reached the conviction that Segundo Guillermo Sandoval Puga was executed by State agents outside of any legal process while in detention. For this reason, it declared him a victim of human rights violations.