The US congress is expected to put pressure on the FBI to release the working details of its controversial "Carnivore" email monitoring system at a hearing Monday, reports the Wall Street Journal.
The FBI has reportedly claimed that revealing this information will weaken Carnivore's capabilities and may also infringe copyright protections.
FBI officials will answer questions from a House judiciary committee panel as part of an investigation into the use of the system.
According to available information, Carnivore is a device capable of sifting through millions of email messages in order to gather evidence on suspected criminals.
Opponents say that it potentially violates the rights of innocent Internet users and is open to abuse.
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