COUPLES WHO KILL on Investigation Discovery every Tuesday @21:00

Serial killers do not always go about their business alone -- sometimes they work in pairs. Meet the predators who seduce an accomplice before embarking on a deadly rampage, as forensic psychologists and criminal profilers reveal the true stories of the deadly duos whose killer chemistry leads to murder. This fifth series includes the case of a couple who caused carnage in a chain of pizzerias, robbing stores and then shooting or drowning their employees. Find out what sparked Chrystal and Chuck’s Thanksgiv