The stories behind three extraordinary police cases and how detectives solved them.

Dena Thompson, aka The Black Widow, conned hundreds of thousands of pounds from a string of husbands and lovers. When her web of lies unravelled, her solution was murder.

The gang who tried to pull off the biggest robbery in British history spent weeks planning a major heist.

Also, the horrific murder of a young woman, whose body was dismembered and never found. Show less