The bodies of four people who had been shot dead were found over the weekend in an abandoned house in a Rio de Janeiro suburb by police, Brazilian officials said.
The victims - three men and a woman - were shot dead and left inside the house in Japeri, a city in the Rio de Janeiro metropolitan area.
One of the victims was identified as the 15-year-old son of an evangelical minister and another was a 16-year-old boy.
The other two victims appear to be an older couple, but investigators have not identified them yet, police said.
The house where the bodies were found is used for drug sales and consumption, neighbors said.
Police found cocaine and a shell casing from a .38-caliber revolver next to the bodies, media reports said.
Officers went to the house Sunday after receiving an anonymous tip.
Investigators are looking at the possibility that the victims were drug users who owed money to dealers.