When a number of elderly people were found dead in their beds at properties across south London, New Scotland Yard detectives soon come to realise they are dealing with a serial killer.

The true crime documentary series begins by looking at the case of David Morley, a survivor of a nail-bomb attack in 1999, who was beaten to death on London's South Bank in 2004.

When Geeta Aulakh was fatally attacked on the way to pick up her children and her body mutilated, Detectives tried to find a motive. The case took a new direction after an informant came forward.

When dismembered body parts were found in bins on a residential street in Camden, London, detectives had to investigate quickly before the killer could strike again.

This edition examines the case of Laila Rezk, who was discovered by her son and daughter badly beaten in her own home and died despite all efforts to revive her.

When finance manager Cathy Marlow's body was discovered at her office, detectives shut down the whole office block to scour every inch for clues to find her murderer.

Police investigate the murder of Nisha Patel-Nasri, unraveling a shocking web of lies as they try to uncover the truth.

The investigation into the disappearance of 14-year-old Alice Gross - a case which sparked one of the largest search operations in years.

When Gagandip Singh's body was discovered in a burnt-out car, detectives found out that his father had been murdered on a business trip, and search for connections between their deaths.

A re-investigation into the case of Michael Menson, who was found by police on fire. His family campaigned for justice for two years to prove that his death was no accident.