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.

Take a look back at the 2010 case of 24-year-old Jennifer Pan, a woman accused of trying to have her overbearing parents killed, as once featured in Oxygen's Snapped: Killer Couples. 

When an accomplice to murder "crumbled like a rose petal in August and confessed," the deadly dynamics of Patricia Sexton and her Texas clan shocked police.

“She trusted in him, and she figured he’s done some things, but [was] willing to look past it in the name of love,” childhood friend Dylan Aller said on Snapped: Killer Couples of Amanda Noverr, who helped her husband murder retirees on vacation.

The murder of Susan Bailey was sparked by a complicated relationship among teenagers that involved threesomes and drinking each other's blood.

“They were an explosive couple that each fed off the other and I don’t think the crime would have happened without the passion they had,” defense attorney Kevin McCants said on Snapped: Killer Couples of Shanika Robinson and her boyfriend, who helped to brutally murder her brother-in-law.

“The murder happened in her home, and she had to have known about it,” Robbie Fox, former Sevierville police chief, said on Snapped: Killer Couples, as Shayne Lovera claimed she was innocent. “There was no way for her to get around that.”