Updated

Police found the bodies of seven youths showing signs of torture inside a car on this city's poor north side and said Friday they apparently were slain by gang members from a rival shantytown.

According to reports in the local press, the victims found Thursday night in Del Castilho were members of a shantytown soccer team that had been kidnapped on Thursday night when they went to play a game in another neighborhood.

Press reports suggested the youths, aged from 14 to 18, were killed simply for coming from an area controlled by a rival drug gang, but were not involved in trafficking.

But police spokesman Renato Barone said investigators believed the victims were members of a rival drug gang and that relatives were circulating the story of the soccer team as a coverup.

"The theory we're working with is a war between drug gangs," Barone said. "They don't just kill and torture people who had nothing to with anything."

Barone said he could not confirm local press reports that the victims had been decapitated, though he said there were signs of torture.

Another youth who was with the victims when the kidnapping occurred but was able to escape reported the killings to police, Barone said.

Most of Rio's over 600 shantytowns are controlled by heavily armed drug gangs who often battle over lucrative drug-dealing spots.

In recent months, paramilitary militias formed by retired and active police and soldiers have also entered the picture by trying to take control over the shantytowns, eliminating the drug trade but charging residents for protection.

A spate of gang violence in December that left 19 people dead was blamed by authorities as drug gangs' reaction to these militias.

Barone denied the killings had anything to do with recent police operations in the Complexo de Alemao slum which left five alleged traffickers dead on Wednesday.

Rio de Janeiro is one of the most violent cities in the world, with an annual homicide rate of around 50 per 100,000. For youths between 15 and 24, that rate climbs to 94.3 per 100,000.

Click here to go to FOXNews.com's Americas Center.