On the night of October 27, 2020, Lissa Maria Caiza poisoned her two children, aged nine and five, in an apartment she rented in Pifo, a rural parish in the northeast of Quito. She had written a letter to their father. "I don't know if we will go to heaven, to hell, or if it will all just be a dream," it read, "but I know that for me this moment is hell. I don't expect you to forgive me; I know you hate me, and now you will hate me even more." She telephoned him to say she had written to him and would be taking what was hers, meaning the children. At two in the morning she called him again to ask for help, saying she felt ill after swallowing a toxic substance. Neighbors heard her calling for help. An hour later a police officer told the father to come to Pifo. Firefighters had found Caiza close to death, and the children were found dead on the bed at first light. The investigation found they had died of mechanical asphyxia and poisoning, after taking toxic substances mixed with medicines.
Officers searching the apartment found a third body. Jaime Geovanny Yanchaguano, twenty-eight, described in the case as her boyfriend, was wrapped in blankets and pushed under a sink, the bathroom sink by some accounts and the kitchen counter by others. He had been dead at least four days. He had disappeared on October 18, and his family had been receiving calls and text messages demanding eight thousand dollars for his return, saying a drug trafficker had kidnapped him. Prosecutors said Caiza had orchestrated those demands herself and had acted alone. She said nothing throughout the case; the fingerprint comparisons on the two blankets that wrapped the body were what the prosecution relied on. He had been asphyxiated, probably after ingesting a substance first.
On December 22, 2020, appearing by video from the prison at Latacunga in an orange uniform, she was sent to trial for the children's deaths, and the letter was read out. Her defense argued that the children had died of Covid-19, an illness both had already had and recovered from, and the prosecution's expert evidence ruled it out. The psychological assessment found no disorder and reported that she was oriented in time and place when she acted. She denied killing them. On August 3, 2021, the Tribunal de Garantias Penales de Pichincha convicted her of murder under article 140.1 of the penal code and sentenced her to thirty-four years and eight months, with twenty thousand dollars in reparation to the children's father. The prosecutor, Elba Garzon, had asked for the aggravated maximum.
The Yanchaguano trial followed in April 2022 and produced a further twenty-two years. At the preparatory hearing her defense lawyer had said no witness saw the killing and that nothing proved he had been given any substance. The lawyer for his family, Valeria Mena, said the investigation by three officers of Dinased, the national homicide unit, had established otherwise. A forensic psychologist told the court that the aim had been to frighten the family into paying rather than to kill, and that the plan had got out of hand.
She was linked to two other deaths in and around the same parish that year, and to other poisonings. Marco Escanta, forty-eight, a former workmate and lover of hers, was found dead in his house at Florida de Chantag in Pifo on June 20, 2020, with beer bottles and a glass bearing her fingerprints; that case went to separate proceedings, and a May 2026 report says she has also been sentenced to twenty-two years over the killing of a man it names as Marco Bayardo. Jose Luis Erazo, forty-two, was found dead in an apartment at Checa, also northeast of Quito, on May 28, 2020; his death was first recorded as a heart attack, and his family, who believe he was her first victim, filed a complaint that has stalled. A woman named Norma, a flower-farm worker who had lost her job in the pandemic, told a Quito paper that Caiza had tried to poison her too, in Pifo that October, and that her stomach still suffered from what she swallowed. Reporting at the time credited Caiza with attempted poisonings of at least ten people in Pifo.
Her appeal against the first sentence was rejected, the National Court of Justice turned down her cassation, and the conviction was ratified. In January 2026 her lawyers filed again, this time not against the prison term but against the twenty thousand dollars, and the petition was assigned to a specialized chamber. She is held at the Centro de Rehabilitacion Social de Latacunga in Cotopaxi.