For Brazilians weary of crime, the latest wave of violent attacks on the wealthy has come as a shock - the gang members are the privileged rich children of the country's elite.
Called the "silver spoon gangs" by police, the groups steal cars or target the houses of the rich and famous, including the speaker of the Brazilian Senate and the singer Dionne Warwick.
Last week, police arrested the 25-year-old son of a business tycoon whose 46-man squad robbed homes in seven states and is allegedly responsible for nearly a dozen murders.
Mauricio Chaves de Silveira started his life of crime after meeting his girlfriend, Jacqueline Rodrigues, who is nine years his senior. Together the two encouraged friends - including a lawyer - to join their gang, which specialised in violent house thefts in the most exclusive areas of the country.
Their eight-year crime rampage was so successful that police feared the group might eventually decide to escape abroad with their booty.
Only when one gang member was caught did police finally manage to arrest the group. (He had surgically scraped off all identifying prints except the one on his little finger.) Humberto Guimaraes, head of police for robbery and car thefts in Rio, said: "Mauricio's gang of wealthy kids is not the only one we have identified. We now estimate that at least 10 of these super-gangs are operating in Rio alone.
"They are exclusively made up of educated people who have had a privileged upbringing."
According to Guimaraes, the silver spoon gangs are responsible for half of the 1,539 cars stolen in Rio last month. Their members are believed to have attended the city's best schools and belong to some of its most respected families.
Police say that the gangs attract members with expensive drug habits or those who want to impress their girlfriends.
"Sometimes even a generous allowance won't finance a drug addiction," said Guimaraes. "And sometimes all these kids want is a nice weekend with their girlfriends in a brand new car."
Although most of the car thefts are carried out without weapons, the silver spoon gangs are known for their violence when committing house robberies. Often victims are tied up, threatened at gunpoint and on numerous occasions have been killed - despite having already handed over all their valuables.
"We know that these rich gangs have tenuous links with drug traffickers who call them the Playboys", said Guimaraes. "They buy their weapons in the slums and in return they give the traffickers a cut of the profit from the robberies."
Although a small percentage of wealthy children has always drifted into crime, the authorities say that the number of silver spoon gangs has steadily increased during the past five years.
Judge Guaraci Vianna, who sits in a youth court in Rio de Janeiro, says many of the rich youths in the dock are socially alienated youngsters who have nothing to do and no ambitions.
"When I was younger we joined political movements against the dictatorship, but now the young have nothing to fight for. Of every 100 teenagers that I see in court, around 30 are from good addresses. Five years ago, the figure was about five in every 100. When parents look at their child's criminal file they cannot believe it because they have no idea what their boys are up to. Some actually feel guilty for the crimes committed by their children."
For Mauricio's father, Gelson Silveria, there is no question of trying to influence the outcome of the impending criminal proceedings against his son. He told an employee that since his son left the family apartment last June, he had repeatedly given him fresh chances to mend his criminal ways, even helping financially on a number of occasions. Now he refuses to have anything to do with him, saying Mauricio is dead in the eyes of his family.
Gilberto Velho, professor of anthropology at the Federal University of Rio, believes that Brazil's middle class are experiencing a crisis of values, a result of the country's recession.
"We know that poverty is not a determining factor in criminality. I think that these wealthy children are turning to crime in greater numbers than ever because consumerism affects them more strongly than any other social class.
"They are motivated to acquire many goods because that is the way success is measured. That's why they turn to crime because without these things they are a failure."
The vast majority of Rio's 10 million population live in poverty in one of the many slums that line the city. The state's department of labour believes that the unofficial jobless rate is currently around 18 per cent.