Rio de Janeiro's public defenders' department says the Brazilian state has accumulated more than 60,000 unsolved murders in the last 10 years.
The department investigated the matter for the federal Ministry of Justice as part of a national plan to improve public safety.
The survey shows that 24,000 of the victims haven't even been identified.
Creation of a special homicide division in the city of Rio de Janeiro did little to improved the solution rate. It went from 11 percent to 14 percent.
Across Brazil, police solve about 8 percent of murders. In the United States and in European countries the rates are reportedly around 70 percent to 80 percent.