Updated

Police in Brazil's most populous state can no longer give first aid to victims injured in violent crimes or in shootouts with law enforcement officers.

Sao Paulo State Public Safety Department says in a statement posted on its website that as of Wednesday only emergency response teams and paramedics can provide treatment to victims at the scene of the crime or shootout with police.

Department head Fernando Grella Vieira said the state government enacted the measure "to safeguard the health of victims and guarantee the preservation of the crime scene for forensic investigations."

Sao Paulo State Police commander, Col. Marcos Chaves said the measures would make police actions "more transparent."

"Officers are always seen with suspicion whenever there is a shootout with police. No one knows if it actually occurred and if the scene of the crime was altered. The new measures will end these suspicions," Chaves told reporters.

State legislator Olimpio Gomes, a former police officer, told the Folha de S. Paulo newspaper that the measure "shows the government does not trust police."

Sociologist Nancy Cardia of the University of Sao Paulo's Center for the Study of Violence welcomed the new measures.

"It could reduce the number of people killed by police and help determine if police abused their power in a shootout," she told the G1, the Internet portal of the Globo TV network.

For Human Rights Watch, the New York-based rights advocacy group, the measure is an "important safeguard against unlawful killings by state police,"

Efforts by Sao Paulo police "to contain violent crime have too often been undermined by fellow police who themselves engage in unlawful killings," said Jose Miguel Vivanco, the group's Americas Director said in a statement posted Wednesday on the organization's website. "The new rule will make it harder for these officers to cover up their crimes by pretending to rescue their victims before forensic investigators arrive."

In late November, Human Rights Watch said Brazilian police routinely "engage in unlawful violence, executing people and falsely claiming they died in shootouts."

A 2008 United Nations report found that that police throughout Brazil were responsible for a "significant portion" of 48,000 slayings the year before.

In a bid to curb such killings, Brazil's Human Right Defense Council last year released a resolution outlining steps to be taken in killings in which police allege the victim resisted arrest. Those include such seemingly basic tasks as promptly analyzing the crime scene and collecting witnesses' statements. Analyzing autopsy reports, as well as any weapons or vehicles involved in the incident, are also among the recommended steps.