Brazil police find 5 bodies inside car in Rio de Janeiro slum , 1 was headless

Brazilian police have found the bodies of five men inside a car abandoned in one of the slums of Rio de Janeiro. At least one body was decapitated.

Police say in an email that they're investigating what appears to be retribution by one drug gang against members of another gang for the death of a 17-year-old boy in the same area earlier this week.

A message was scribbled on a pizza box left on the car. It read, "A life for a life" and "you killed an innocent."

Thursday's discovery adds to an upsurge of violence in Rio's already turbulent slums.

Gangs are increasingly staging attacks against one another and on police who are trying to create permanent posts in many slums before the 2016 Olympics.