Expertise on family cell phones will guide the investigation into the death of a boy who was poisoned in Baixada do Rio de Janeiro
The Baixada Fluminense Homicide Police Station (DHBF) awaits the results of the analysis of cell phones belonging to the family members of Arthur de Mello da Silva, aged 11. The boy died after a period of 11 days admitted to the Ricardo Cruz State Hospital (HerCruz), in Nova Iguaçu. Although the death certificate indicates bronchopneumonia as the cause, toxicological tests revealed the presence of lidocaine (an anesthetic), midazolam (a sedative) and terbufos-sulfoxide, a pesticide, in the child’s body. The combination of these compounds, atypical for a natural condition, reinforces the suspicion of poisoning and should guide the next steps of the investigation.
The mobile phone devices, which belong to Arthur’s father, mother, stepmother and stepfather, were collected last Friday. On the same day, the possible crime scene was mapped in detail with a laser scanner and genetic material was collected for future analysis.
Police authorities seek to reconstruct the last moments of Arthur’s life and determine how the chemical substances were introduced into his body. One of the lines of investigation suggests that the boy may have ingested a piece of cake that contained the poison.
According to testimony given by lawyer Luiz Almeida, who represents Ademir Mello, the child’s father, Arthur had lived with his father and stepmother since March of this year. Previously, he had lived with his father between November 2025 and February this year, during the school break, before returning to his mother’s house.
Still according to the father’s defense, Arthur’s mother would have contacted Ademir asking her son to live with him again, claiming that coexistence in her house was troubled. From then on, Arthur remained at his father’s residence, visiting his mother on weekends. On the last weekend he was with his mother, the agreement was that he would return to his father on Sunday, but, due to a school meeting on Monday, his mother took him directly to school. After classes, Arthur took the bus to his father’s house.
Security camera footage obtained by the investigation shows the boy arriving at his father’s house at around 6:20 pm. There were his father, stepmother and 4-year-old half-brother at the scene. Shortly afterwards, her stepmother’s 9-year-old stepdaughter would also arrive.
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The lawyer reported that, upon arriving home, Arthur had confided in his father that his stepfather had threatened to leave his mother if he returned to live with her. Ademir would have reassured his son, asking him not to worry about the situation.
Shortly afterwards, while the father went out to pick up his stepdaughter from a tutoring class, the stepmother found a piece of chocolate cake in the boy’s backpack. According to the defense, the food was stored without a suitable container, among the folded clothes, which attracted attention. The stepmother would then have informed her husband about the cake over the phone.
According to the lawyer’s report, Arthur consumed the piece of cake, telling his father that his mother had saved it for him, as she had not been able to eat it at the party on Saturday and Sunday because she was feeling ill. Arthur’s father, according to the lawyer, never saw the cake. Later, the family had pasta and ground meat for dinner, a meal that was consumed by everyone present in the house.
Hours later, around 11pm, the boy began to show the first signs of feeling unwell. The father’s version describes vomiting, episodes of diarrhea and a state of mental confusion, with Arthur uttering meaningless sentences. He was taken for medical care and transferred to a more complex health unit, where he remained hospitalized until the day of his death.
