Notorious: Charles Cullen
Nurse Charles Cullen is one of America's most prolific serial killers. Police say he may have murdered up to 400 victims, Cullen claimed he acted mercifully. An in-depth look into the case reveals the truth behind his motives.
More from Season 23
Episode 1
Shajia Ayobi
Does a shocking carjacking have ties to international espionage? Or will the murderer turn out to be someone much closer to home?
Episode 2
Sonia Mitchell
When a young father goes missing, authorities suspect his illegal activities, but a revelation about the mother of his children turns the investigation upside down.
Episode 3
Kimberly Ross
A generous couple opens their home to help others, but a deadly home invasion raises questions about lies and conspiracy under their roof.
Episode 4
Shelly Arndt
A deadly fire destroys a home and leaves one man dead, but investigators suspect the fire was an inside job.
Episode 5
Verginia Turner
A possible love triangle has deadly consequences for a prominent California lawyer.
Episode 6
Melissa Napier
When a determined son urges police to investigate the disappearance of his father, he is met with a storm of family tragedy and betrayal.
