‘Devil Among Us’ Preview Thursday On Investigation Discovery

· Trail of Blood premieres Thursday, July 30 at 9/8c In December 1978, police in a Denver suburb find Nancy Spangler and her two children dead in an apparent murder-suicide. A note penned by Nancy seems like a confession, and it’s ruled a terrible tragedy. Fifteen years later, Donna Sundling falls to her death in the Grand Canyon. It looks like an accident until investigators, spurred on by her grieving family, look closer at her life. They realize the haunting truth about not only what happened to Donna, but the connection that goes back decades to the deaths of Nancy and her children.

Season Finale: Blood Brothers premieres Thursday, August 6 at 9/8c A serial killer stalks Orange County, Calif., targeting the homeless. Meanwhile, a young man stands accused of murdering his family. Investigators must race to find the crucial link between the cases: can they catch the predator, and free an innocent man in the process?