When honors student Monica Diaz, 16, met boyfriend Michael Naranjo, 17, in a high school ROTC program, their connection quickly turned sinister.

A criminal fell hard for a suburban mom and was willing to do her bidding — even if that meant murder, as seen on Snapped: Killer Couples.  

When a Gulf War vet and his girlfriend befriended a “beautiful” but troubled teenager in a local bar, jealousy led to murder on Snapped: Killer Couples.

“Sometimes you can be sleeping with a snake and don’t even know it,” said the family of slain nurse Carla Knowlton on Snapped: Killer Couples.