"Falling in Love with Your Source"

Intelligence case officers are regularly reminded not to "fall in love with your source." In the trade jargon, that phrase refers to losing objectivity about the accuracy of information and the honesty and motivation of the source providing it. Rarely, however, does a case officer develop a trusting, intimate relationship with a source. Sometimes they do, and when that happens, the outcome is almost always disastrous.

A reasonably good account of how it can happen is found in A Review of the FBI's Handling and Oversight of FBI Asset Katrina Leung. This account is the May 2006 redacted declassified report of the US Department of Justice, Office of Inspector General.