Gastón Mansilla Yupanqui

Gastón Gabriel Mansilla Yupanqui (born 1991), is a Peruvian university student. He studied at Universidad Nacional Federico Villarreal. He killed Víctor Ríos Acevedo (a.k.a. Niño Viejo/Old Boy) on Saturday January 7, 2012 in an apparent act of self-defense near the intersection of Tacna Avenue and Colmena Avenue, in Lima, Peru.

According to Mansilla, two muggers approached him armed with switchblades

Mansilla was arrested and charged with second degree murder and/or violation of the Peruvian Law of Proportionality, Education Faculty dean Manuel Asmat and Congressman Juan Díaz Dios presented a writ of habeas corpus on Mansilla's behalf. Classmate Marco Vargas Romero labeled the judge's decision, "unbelievable" "surprising" and "arbitrary". Several other Congressmen also spoke in Mansilla's defense, including Renzo Reggiardo, who criticized Judge Asunción Puma León's decision to order Mansilla's arrest, and Víctor Andrés García Belaúnde, who said the court's decision to imprison Mansilla is an "abuse" that must be sanctioned by the Office of the Control of the Magistrate (OCMA).

Congressman Díaz indicated that he would send a report to OCMA and to the president of the Justice System.

On 12 January 2012, José Luis Pérez, head of the Instituto Nacional Penitenciario (INPE), received a judicial order for Mansilla's release issued by Juan Carlos Aranda Giraldo, who presides over the second penal court, revoking the detention order. Mansilla was liberated on 13 January 2012. The judge turned in her letter of resignation at that time, but this did not end the disciplinary investigation against her.