Niecy Nash plays Glenda Cleveland, a neighbor of the serial killer who called police several times, in Netflix's  "Monster: The Jeffrey Dahmer Story." But was Cleveland a real person?

"Shadowland," a new docuseries on Peacock, explores the forces that drive people to extreme beliefs, often upending their own lives in the process.

Leni and Gina, the twins in the new series "Echoes" on Netflix, aren't strictly fictional. There are real life siblings who also share deep — and possibly murderous — secrets. 

The upcoming Peacock documentary "Sex, Lies and The College Cult," will delve into how Lawrence Ray was able to move into his daughter's college dorm, gain psychological control of her friends and form a sex cult.