José Roberto Martínez Vásquez (19 April 1976 – 13 December 2002), known by his friends as "Tila" and posthumously referred to as the "Psychopath of La Dehesa" was a Chilean serial rapist and robber.

Born and raised in poverty, he would usually target high-class homes (usually located in Central Santiago, Las Condes, Vitacura, and Lo Barnechea) as part of a social vendetta.

At 17 years old, he escaped from the San Miguel Diagnostic Orientation Center (Centro de Orientación Diagnóstica, COD), after which he was captured and transferred to the section for minors in the Puente Alto prison.

After tying up his victims, the home's residents, he felt frustrated by his lack of collaboration, for which he raped the woman of the house in front of her husband (already forming his modus operandi) and went to sleep.

[2] On May 8, 2002, the remains of Maciel Zúñiga Pacheco, the then-partner of Roberto Martínez, were found in the Uno Sur passageway in the José María Caro population in Lo Espejo.

[4] He was confined in the Colina II Penitentiary Compliance Center until 13 December 2002, when, during a power outage, he took his own life by hanging himself with the cord of an electric typewriter.