Valparaíso school shootings

On the morning of 17 December 1999, Iván Arancibia Navarro, a 47-year-old physics teacher who had recently been removed from teaching duties by the Municipal Corporation of Valparaíso (CMV), carried out a spree killing at two educational sites in Valparaíso, Chile. Earlier that morning he had distributed pamphlets at the Catholic University of Valparaíso describing a claimed free-energy device, behavior later cited as evidence of his deteriorating mental state.

At 11:15, Arancibia arrived at his former workplace, the B-29 Valparaíso high school, then in use as a venue for Chile's national university admissions exam. Accompanied by his three-year-old daughter, Verónica Tamara Arancibia Aguad, and carrying a pistol concealed in a wrapped box, he entered the office of school director Eliseo Francisco Nogué Gutiérrez and shot him three times, killing him. He then shot and killed his daughter. A garbage bag used to muffle the gunshots meant the killings went undetected for roughly 25 minutes.

Arancibia then walked to the nearby Eduardo de la Barra Valparaíso high school, headquarters of the CMV, where he shot and killed the CMV's education director, Luis Agustín Inocencio Alvear, with four rounds. He then confronted CMV manager Víctor Quezada but, having exhausted most of his ammunition, turned the gun on himself, firing a round into his own mouth. He survived the suicide attempt, losing vision in one eye, and was hospitalized for two months.

Arancibia was formally arrested on 20 December 1999 and prosecuted for two counts of qualified homicide and one count of parricide, carrying a potential sentence ranging from 35 years to death under Chilean law at the time. Psychiatric evaluations in 2000 initially found him unfit for trial; the case was reopened after appellate review determined he could stand trial. On 7 September 2001, Judge Jaquelinne Nash acquitted Arancibia, ruling that he suffered from delusional psychosis and was not guilty by reason of insanity. Alejandro Nogué, son of victim Eliseo Nogué, publicly criticized the ruling, saying Arancibia "should be in prison."

Following the acquittal, Arancibia was committed to the Dr. Philippe Pinel Psychiatric Hospital in Putaendo before eventually being discharged and moving to his parents' home in Viña del Mar. He died by suicide on 27 December 2011. The mother of his daughter, Heidi Aguad, later stated she had forgiven him.

The incident is described as the first and deadliest school shooting recorded in Chilean history.