Sandra Melgar & Other Female Serial Killers

Two days before Christmas, in 2012, Sandra—or Sandy—Melgar was found tied up inside of a closet in her home in a nice neighbourhood of Houston. A chair was forced against the doorknob, keeping her trapped in the confined space. Her husband Jaime—Jim—Melgar had been stuffed into a different closet—but unlike Sandy, Jim had been killed, first. A medical examiner's report concluded that Jim had died of blunt force trauma, and multiple stab wounds that had been inflicted with a kitchen knife. The community was horrified, and their horror only grew when police announced that they'd identified the person responsible for the attack on the Melgar family—Sandy Melgar, herself.

Why did she do it?