Devices could be used to disable phone towers and facilitate anonymous, encrypted communication between potential threats and criminal enterprises, the agency said. “It can’t be understated what this system is capable of doing,” said Matt McCool, the special agent in charge of the Secret Service’s New York field office. “It can take down cell towers, so then no longer can people communicate, right? Officials said there are no known credible threats to New York City. The New York Police Department, the Justice Department, Homeland Security Investigations and the Office of the Director of National Intelligence are investigating.