Follows Catherine Jensen, a recently promoted homicide detective who enlists the help of Thomas Schaeffer, a forensic psychologist, to track down serial killers and relentlessly seeks the truth behind the disappearance of her brother.

A true-crime series that examines the story of sadistic and meticulous killers who plan their victims’ murders for weeks, months or even years. Each stand-alone episode is brought to life through a tapestry of firsthand interviews with investigators and those close to the victim. Over the course of the hour, we’ll follow detectives on a winding investigation.

Former Rhode Island police Sgt. Derrick Levasseur and forensic psychologist Kris Mohandie answer the pleas of desperate families and investigate murder cases that have officially gone cold.

"Kill or Be Killed" reveals the stories of those who lost their lives at the hands of someone they knew, who then claimed it was self-defense. In these complex cases, the lines between murder and justifiable homicide are blurred, making them some of the hardest cases to solve. When the killer is the best and sometimes only witness, investigators must scrutinize every other detail. Law enforcement, prosecutors and defense attorneys unravel every detail, from the harrowing stories, forensics, interrogations and witness statements that led up to the gruesome event in order to find answers.

Rachel Burke is a criminal profiler, one of the best, actually.

She, along with a sophisticated team of specialists on the FBI's Violent Crimes Task Force in Atlanta, investigates crimes throughout the country.

Together, they solve the toughest of cases while trying to live their lives as best they can.