On October 1, 1973, three individuals were arrested by civilians and Carabineros personnel from the Schleyer police station at the home of one of them:

José Gregorio RETAMAL VELASQUEZ, 21 years old, student at the Escuela Normal.

Patricio Lautaro WEITZEL PEREZ, 26 years old, watchmaker, member of the Juventud Radical Revolucionaria. He had been detained prior to September 11, accused of being the perpetrator of an attack on a radio station in Chillán, and was released on September 18 of the same year by the Minister in charge of the investigation due to a lack of evidence.

Arturo Lorenzo PRAT MARTI, 21 years old, student at the Escuela Normal and member of the Juventud Radical Revolucionaria.

Despite the efforts of their relatives, the presence of the detainees was not acknowledged at any facility. On December 24 of that year, Patricio Weitzel's father found a group of at least nine bodies, bound with wire and bearing gunshot wounds, on the banks of the Ñuble River at the El Ala bridge.

Among them, he recognized his son's body and hid it provisionally. Following his request, on December 26, the judge from Chillán who was presiding over a report of a missing person arrived at the site and ordered the remains to be recovered and transported to the local morgue.

The remains of Weitzel and Retamal were interred in the city cemetery. Weitzel Pérez's death certificate states the cause of death as: "Acute anemia. Multiple ballistic perforations. Homicide." It is presumed that he was killed on the same day of his arrest, as indicated by the watch he was wearing.

Regarding the third detainee, Arturo Prat Martí, there was no news following his arrest, although it is reasonable to presume that he met the same fate as those who were apprehended alongside him.

The Commission formed the conviction that the execution of Weitzel and Retamal and the forced disappearance of Prat at the hands of State agents constituted grave violations of human rights. This conviction is based on the fact that their arrests were documented and the bodies of two of them were subsequently identified among several corpses of executed individuals.