Military police officers from the Brazilian State of Sao Paulo have reportedly killed 494 people in the first seven months of 2015, which averages a total of two murders per day, according to the Sao Paulo Security Secretariat (SSP).

“I think everyone needs to pay attention to what is happening and discuss ways to reduce and prevent these killings. The police are there to protect people's lives, but what happens is the opposite, " Sao Paulo State Police Ombudsman Julio Cesar Neves told Brazilian media Monday.

Data from the Brazilian Forum on Public Safety show that between 2009 and 2013, Brazilian police killed 11,197 people – more than the total number of people killed by police in the US over the past 30 years.

During the same five-year period, 1,170 police officers were killed.

The newly released data coincides with an ongoing investigation by federal authorities to determine police involvement in a killing spree, which took place last Thursday in Sao Paulo.

Last week, marked the sixth and deadliest massacre this year in Brazil’s largest city, in which 18 people were shot dead in two neighboring suburbs.

Brazilian authorities are looking into whether the 18 murders were an act of revenge by off-duty officers after the deaths of two colleagues.

Off-duty police officers have been accused of involvement in recent massacres in the Amazonian cities of Manauas and Belem.

Very few public attorneys ever seek to prosecute serving police officers; in the rare instances that they do, juries tend to exonerate them.