The underground world of computer hackers has been so thoroughly infiltrated in the US by the FBI and secret service that it is now riddled with paranoia and mistrust, with an estimated one in four hackers secretly informing on their peers, a Guardian investigation has established.
Cyber policing units have had such success in forcing online criminals to co-operate with their investigations through the threat of long prison sentences that they have managed to create an army of informants deep inside the hacking community.

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