The Killer Within - Episode Guide

14-year-old Kim teamed up with her boyfriend to kill her own mother and sister in cold blood - but why?

What drives a man to murder a stranger? Detectives reflect on the case of Hernandez, who did just that.

What drives a man to kill his wife? Ahmed Al Khatib blamed evil spirits as he plotted to get away with murder. 

Described as charming, detectives saw another side to Shawn Grate when they found two decomposing bodies in his home.

The story of the nurse who confessed to murdering up to 40 patients during his 16-year career

She was trusted to protect the community as a police officer, but ended up committing one of the worst crimes imaginable.

A look at how Wilbern Cooper was able to live a normal life for 28 years, knowing he had brutally killed a person.

A feud between two rival Birmingham gangs comes to a head when two innocent teenage girls are killed.

The shocking story of the murder of French au pair Sophie Lionnet at the hands of the couple she worked for.

12 years after murdering her 87-year-old father in an act of revenge, Barbara turned herself in. What drove her to kill?