By Gary Duffy
BBC News, Sao Paulo
Police said the model helicopter was equipped with nine mobile phones
Police in Brazil have foiled a plot to smuggle mobile phones into a high-security prison using a remotely-controlled model helicopter.
Four people were arrested and the high-tech toy was recovered after police stopped a car near to the jail.
Mobile phones are widely used by prisoners inside jails in Brazil to continue directing criminal activities.
Earlier this year prison guards in the same state discovered that pigeons were being used to carry mobile phone parts.
It seems the plot to smuggle the mobile phones into the Presidente Venceslau high security jail in Sao Paulo state was only stymied when police stopped a car as part of a routine check.
In the boot of the vehicle they found the one-metre long model helicopter with a basket-like container attached to its base.
Inside were nine mobile phones wrapped in a disposable nappy, while another five phones were also discovered in the vehicle.
Four suspects were arrested, and the youngest, who was aged just 17, is reported to have confessed they had been given $5,000 to buy and prepare the helicopter.
They were apparently to be paid the same amount if they had successfully landed the model inside the prison walls.
Prisoners in Brazilian jails routinely use mobile phones to carry on with criminal activity, and the police say the ones they recovered were probably intended to go to gang leaders inside the jail.
It is not the first time that the authorities have foiled an innovative attempt to smuggle material into a jail in Brazil.
Earlier this year Sao Paulo state prison guards uncovered a plot using pigeons to carry mobile phone parts over the walls of a jail.