Gretchen Anthony's family grow suspicious when they receive odd texts from her phone, before things take an incredibly sinister turn. 

At first no one was suspicious when more than two dozen elderly women died in their beds at upscale retirement homes in Texas. Due to their age, the deaths all seemed like natural events. But all that changed when Mary Bartel, 91, miraculously survived an attempt by an intruder who attempted to smother her with a pillow. Her pacemaker kicked in and saved her, and the strong willed, savvy senior citizen was able to give detectives a detailed account of what happened. A stranger identifying himself as a maintenance man pushed the door open to her apartment when she answered. The intruder told her to lie down on her bed. Then he picked up a pillow and smashed it down over her head and chest so intensely that Bartel blacked out. Police later realized while Mary was unconscious, the man rifled through her jewelry boxes, took gold crucifixes and a distinctive gold locket with her dead husband's photo inside — then removed her diamond rings. A tip led detectives to focus on a man seen in the parking lot of Bartel's retirement community. Police surveillance would find Billy Chemirmir tossing an empty jewelry box into a dumpster. Detectives began to investigate reports of stolen jewelry and began to realize they had arrested a serial killer.