The Department of Homeland Security has begun performing polygraph tests on employees to determine who might be leaking information to the media about immigration operations, according to four sources ...

The polygraph examination is a key component of the security clearance process for individuals seeking access to classified information in sensitive government positions, usually within the ...

A version of this story appeared in CNN’s What Matters newsletter. To get it in your inbox, sign up for free here. When President Ronald Reagan’s White House threatened thousands of government ...

Federal agencies have stepped up their efforts over the past few weeks to find potential leakers, and some — like the FBI, the Department of Homeland Security and the Department of Defense — are ...