# Fraud and impersonation investigations in Brazil

> Live situation record from CLSTR: https://clstr.news/situations/fraud-and-impersonation-investigations-in-brazil
> Updated: 2026-08-06T23:00:00.000Z. Sources: 52. Developments: 2.

Authorities in Brazil have conducted several operations targeting various forms of fraud and impersonation.

In São Paulo, police arrested an individual known as "Joker" in Santos for operating mass-calling scams designed to harvest personal data and passwords. In a related investigation in Bahia, authorities searched the home of a man accused of using deep-fake images of a doctor to sell counterfeit medicines and falsified prescriptions.

In Rio de Janeiro, 42-year-old Diogo dos Santos Serpa was arrested in Nova Iguaçu for impersonating Dr. Jeferson Targino Sampaio while providing home care services to a 10-year-old girl with a high-risk malignant brain tumor. Serpa allegedly provided services since approximately October 2025, conducting at least six consultations and charging between R$ 700 and R$ 1,000 per visit. He used the doctor's name and medical registration number to issue prescriptions, request examinations, and provide referrals.

The fraud was uncovered after the child's mother, Cintia Santos Matheus, noticed medical negligence, including a feeding tube that had not been changed for five months. After verifying credentials via the Cremerj website, she discovered the provider's photo did not match the registered physician. Police seized stamps, prescription pads, and documents used in the impersonation. Upon arrest, Serpa claimed to be a 12th-semester medical student.

Following a custody hearing, a judge converted Serpa's arrest in flagrante to preventive detention, ruling that his continued freedom posed a direct risk to the lives of others due to his repeated use of stolen medical identities. Investigations are ongoing to determine if he had connections to the physicians whose identities he misappropriated or to the home care provider, Health+ Cuidados e Gestão.

## Claims

- A judge converted the suspect's arrest in flagrante to preventive detention, citing risks to public safety. (disputed by 2 sources)
- Diogo dos Santos Serpa was arrested for impersonating a doctor while providing home care for a child with a brain tumor. (corroborated by 3 sources)
- The suspect had been providing home care services since October 2025. (corroborated by 3 sources)
- The suspect used the name and CRM number of physician Jeferson Targino Sampaio to prescribe medications and request exams. (corroborated by 2 sources)
- The mother discovered the fraud after noticing a feeding tube had not been changed for five months and finding a photo mismatch on the Cremerj website. (corroborated by 2 sources)
- The suspect charged between R$ 700 and R$ 1,000 per home care visit. (corroborated by 2 sources)
- The suspect claimed to be a 12th-semester medical student at a private university upon his arrest. (single source)

## Timeline

### 2026-08-06: Diogo dos Santos Serpa arrested for impersonating a doctor in Nova Iguaçu

A man was arrested in Nova Iguaçu for impersonating a doctor while providing home care for a child with a brain tumor, using a legitimate physician's credentials to issue medical orders.

48 sources. https://clstr.news/cluster/so-jos-do-rio-preto-police-shootout-kills-two-thieves-in-r300k-theft

### 2026-07-30: Brazil police arrest online fraud suspect known as Joker in Santos

Brazilian police arrested a fraudster known as Joker in Santos, seizing scam software, and separately raided a Salvador suspect using a deep‑fake doctor’s photo for counterfeit medical sales in Bahia.

4 sources. https://clstr.news/cluster/brazil-police-arrest-online-fraud-suspect-known-as-joker-in-santos

---
Cite as: Fraud and impersonation investigations in Brazil. CLSTR, https://clstr.news/situations/fraud-and-impersonation-investigations-in-brazil