A man found guilty of fatally killing a Dallas ISD teacher’s aide has been sentenced to two decades behind bars, bringing a lengthy legal case to a close. Sixto Banegas Matute received his 20-year sentence on October 13 after being convicted of first-degree felony murder in the death of Jennifer Mendez Olascoaga.
The case began in the fall of 2023 when Mendez Olascoaga, a 24-year-old Dallas resident, vanished after being last seen on the evening of September 27 leaving a mobile home park along Highway 175 in Seagoville. Her vehicle was discovered abandoned the following morning on Lawson Road with her purse and phone still inside.
Weeks passed before investigators got a significant break. In mid-October 2023 human remains were found scattered in a wooded area along Lawson Road near Interstate 20 in Mesquite. The Dallas County Medical Examiner’s Office confirmed the following month that the remains belonged to Mendez Olascoaga and ruled her death a homicide. Forensic analysis also detected small bullet fragments within the remains.
Investigators used phone records to build their case against Matute. Records showed a 15-minute phone call and multiple text exchanges between Matute and Mendez Olascoaga around the time she was last seen at a nearby QuikTrip gas station. Cell tower data then placed both of their phones pinging in the same location along I-20 within seconds of each other and later in the area where her remains were recovered.
That digital trail provided enough probable cause for authorities to arrest Matute on January 10 2024. He remained in custody from the time of his arrest through his sentencing date and had accumulated more than 1,000 days of jail time by the time the sentence was handed down.
Matute was ultimately convicted on the first-degree murder charge and will now serve 20 years in a Texas state prison.