Paul Novak's outwardly heroic persona as a post-9/11 paramedic concealed a dark side that culminated in the brutal murder of his estranged wife Catherine in their Sullivan County home.

Malcolm Webster’s wife, Claire, died in a car crash in a remote part of Scotland, and he was apparently inconsolable. When his second wife, Felicity, almost died in similar circumstances in New Zealand and money is missing, suspicions were raised.

Kathy Augustine was a politician serving in the Nevada Senate. Shortly after her husband of 17 years died from complications of a stroke, she married Chaz Higgs, a critical care nurse whom she met while he was caring for her late husband.

Something was wrong at DaVita dialysis centre in Lufkin, East Texas, with a huge increase in code blues. Patient after patient was taken to the nearest hospital, many succumbing to their injuries.

William George Davis, a nurse in Tyler, Texas, was just 32 when he began a reign of terror over patients recovering from heart surgery. Prosecutors claimed that Davis had at least eleven victims, of whom seven died.

When Eric Lloyd died at home, his wife claimed it was from natural causes. Marie Whiston had been looking after him between nursing shifts at their local hospital and was anxious to attribute his death to ill health.