A Greek paradise turns tragic. A dangerous killer could be living next door. Romance and religion are tied to the death of two elderly neighbors. A serial killer is discovered hidden in plain sight. The Royal family is linked to a deadly scandal. A high-speed car chase turns deadly. The new docuseries 20/20 Britain's Most Notorious Crime Investigations reopens six of the UK's most high-profile crime cases, bringing the prestige and journalistic power of ABC News' legendary "20/20" brand to an international audience with premium, character-driven true crime.