Gregg O. McCrary (born September 10, 1945) is a former FBI agent who served from 1969 to 1995, an expert witness and consultant,[1] an author and an adjunct forensic psychology professor at Nova Southeastern University in Fort Lauderdale, and at Marymount University in Arlington, Virginia.
[2] In 2003, he published The Unknown Darkness, a book detailing those cases which he found most important.
[citation needed] During his tenure with the FBI, McCrary was a criminal profiler and threat analyst in Quantico, Virginia.
[2] Since retiring from the FBI, McCrary has served as an expert witness.
[4] British author Colin Wilson dedicated his 1990 book The Serial Killers to Agent McCrary.