Following a recent spate of cases of Brazilian police officers facing accusations of excessive force, Human Rights Watch has appealed to the country’s Attorney General Augusto Aras to ensure that all police killings are investigated independently by prosecutors, the organization announced Tuesday.

The group said in an open letter to Aras that the current system of having civil police probe police killings falls short of international standards. The UN Principles on the Effective Prevention and Investigation of Extra-Legal, Arbitrary, and Summary Executions state in relevant part:

There shall be thorough, prompt and impartial investigation of all suspected cases of extra-legal, arbitrary and summary executions, including cases where complaints by relatives or other reliable reports suggest unnatural death in the above circumstances. Governments shall maintain investigative offices and procedures to undertake such inquiries. The purpose of the investigation shall be to determine the cause, manner and time of death, the person responsible, and any pattern or practice which may have brought about that death. It shall include an adequate autopsy, collection and analysis of all physical and documentary evidence and statements from witnesses. The investigation shall distinguish between natural death, accidental death, suicide and homicide.

In 2022 alone, Brazilian police killed upwards of 6,400 people, HRW said, citing local advocacy group the Brazilian Forum of Public Security.

Maria Laura Canineu, Brazil director at Human Rights Watch, was quoted in a release announcing the letter as having said:

“The deadly law enforcement operations in recent months underscore the urgent need to improve investigations into police conduct … Prosecutors should carry out effective oversight of the police by leading investigations into police killings and cases of suspected police abuse, instead of relying on the police to investigate themselves.”

In its letter to Aras, the group issued a number of policy recommendations, including: Requiring prosecutors to lead all investigations into police killings; ensuring that prosecutors visit the scene of the crime immediately after the incident and participate in the subsequent crime scene reconstruction; requiring prosecutors to take statements from victims, relatives of victims, and witnesses; providing victims and their families with updated information about the investigations; creating accessible complaint mechanisms so that the public can report police misconduct; and employing full-time forensic experts who are independent of the civil police.