A teenage witness and forensic testing have strengthened prosecutors’ theory about the five deaths, though authorities say the motive remains unresolved.
MONTEMORELOS, Mexico — Prosecutors in Nuevo León say forensic evidence and the account of a 14-year-old witness support their theory that social media creator Cinthia Abigail Tamez Rivera killed her partner and three children before dying by suicide, while investigators continue trying to determine what led to the Sept. 30 deaths.
The case has drawn widespread attention because of Tamez Rivera’s presence on social media and posts she made shortly before the deaths. But investigators have not established that those posts explain what happened. Nuevo León Attorney General Javier Flores Saldívar said authorities are still examining phone records, witness statements and other evidence as they reconstruct the family’s final hours and look for the source of an apparent dispute before the shootings.
Authorities found five people dead at two locations in Montemorelos, a municipality south of Monterrey. Tamez Rivera’s partner, Leodegario Moya Garza, 28, and two children were found inside a residence in the Los Nogales area. Tamez Rivera and her youngest child were later found dead inside a Jeep in the Los Fresnos area. Early reports differed on the children’s exact ages, and prosecutors have described all three as minors.
Flores Saldívar has said the prosecution’s main theory is that Tamez Rivera first shot Moya Garza and two of the children inside the home, then left with the youngest child. Investigators believe that child was killed at the second location before Tamez Rivera died by suicide. Authorities recovered a .38-caliber handgun, and ballistic testing linked evidence from the residence with evidence from the vehicle, according to the prosecutor.
Investigators disclosed another major piece of evidence this week: a 14-year-old boy was inside the home during part of the violence and survived. Flores Saldívar said Wednesday that the teenager witnessed one of the killings and later questioned Tamez Rivera about what had happened. According to the prosecutor’s account of the boy’s statement, Tamez Rivera indicated that she was angry before leaving the residence. Authorities have not established what caused that anger or whether it amounted to a motive for the deaths.
The teenager was described in local reporting as the son of one of Tamez Rivera’s former partners and had been in her care. Investigators have not publicly identified him because he is a minor. Earlier reports said he hid inside the residence during the violence. Flores Saldívar said investigators interviewed the boy as part of the case, making his account an important element in the effort to reconstruct what occurred inside the home.
Prosecutors also released information from toxicology testing. Flores Saldívar said tests detected a small amount of alcohol and traces of controlled medication, including clonazepam, in Tamez Rivera’s system. Authorities have not said that those substances caused the violence, and the findings do not by themselves establish why the killings occurred. Investigators previously said a gathering had taken place before the deaths and that they were examining evidence of alcohol consumption and a possible family disagreement.
The case initially produced conflicting accounts because the bodies were found at two separate scenes. Early coverage identified Tamez Rivera among the victims without a clear account of who was responsible. As investigators reviewed ballistic evidence, surveillance material and witness information, prosecutors increasingly focused on the theory that she was responsible for the four other deaths. That assessment is an investigative conclusion in a case in which the suspected perpetrator also died, rather than a finding reached through a criminal trial.
Authorities have also carried out additional searches connected with the investigation. A specialized prosecution unit searched a Montemorelos property associated with the surviving teenager, and investigators seized items for further examination. Officials have continued reviewing phones and other evidence recovered during the inquiry. Prosecutors have not publicly identified evidence from those later searches that establishes a different sequence of events or the participation of another person.
Tamez Rivera had built an audience on TikTok by posting about her daily life and family activities. A post made before the deaths contained language about anger, retaliation and self-destructive behavior, drawing intense attention after the family was found. Prosecutors, however, have not said the post proves motive or establishes what triggered the violence. Reports about Tamez Rivera’s financial activities have also circulated, but authorities have not publicly tied those dealings to the deaths.
As of Wednesday, prosecutors said their forensic findings remained consistent with the theory that Tamez Rivera carried out the four killings before dying by suicide. Investigators were continuing to analyze telephone data and other evidence in an effort to determine what happened before the shootings and why. No final motive has been announced.
Author note: Last updated October 7, 2026.