“Mo” made threats to detonate bombs at universities and airports across the U.S., communicating via e-mail, video chat and an Internet-based phone service without revealing his identity or location. The Washington Post says the FBI designed malicious software to be delivered secretly when Mo signed on to his Yahoo e-mail account, from any computer anywhere in the world. The goal of the software was to gather a range of information — Web sites he had visited and indicators of the location of the computer — that would allow investigators to find Mo and tie him to the bomb threats.
Such online surveillance pushes the boundaries of the constitution’s limits on searches and seizures by gathering information without direct connection to a crime. A federal magistrate in Denver approved sending surveillance software to Mo's computer last year. Not all such requests are welcomed by the courts: An FBI plan to send surveillance software to a different suspect was rejected by a federal magistrate in Houston, who ruled it was “extremely intrusive” and could violate the Fourth Amendment. “You can't just go on a fishing expedition,” said Laura Donohue, a Georgetown University law professor who reviewed three recent court rulings on FBI surveillance software.