Isaías Alejandro Villarroel Mella died that day at 2:46 hours, while being transported to the Lirquén Hospital, due to a gunshot wound to the face, cervical spine, and spinal cord, as stated in the Medical Death Certificate from the Legal Medical Institute. The Autopsy Protocol likewise concludes that the wound received was of a "homicidal nature."

According to eyewitnesses, in the early hours of December 23, 1984, Isaías Villarroel was witnessing a street fight on a public thoroughfare in Lirquén.

Officers from the local Carabineros station arrived at the scene and immediately fired several shots, one of which struck Isaías Villarroel, who passed away moments later while being transported to the local hospital's emergency department.

The investigation initiated by the Second Military Prosecutor's Office of Concepción against the Carabineros officer who fired the shot was temporarily dismissed.

The Superior Council, considering that by firing, the State agents did not foresee the consequences that could arise from the use of their firearms against a group of unarmed people, reached the conviction that Isaías Alejandro Villarroel Mella was a victim of the reckless use of force. For this reason, it declared him a victim of human rights violations.