When an autopsy revealed high levels of insulin in Eric Lloyd's body, police realised his widow, nurse Marie Whiston, had been using her medical skills not to care but to kill.
The case of care worker Bunthawee Rimmer, who enjoyed a comfortable lifestyle as a live-in carer to Paul Norfolk. When she was made the main beneficiary in Paul's will, Rimmer stood to inherit almost £350,000 and resorted to a hammer attack to ensure he would not change his mind.
The murder of politician Kathy Augustine, who died after being given paralysing drug succinylcholine by her husband Chaz Higgs, a professional nurse.
Care worker Thelma Purchase plotted with her son and a friend to murder disabled Greg Baker who Purchase once worked for. She knew he couldn't defend himself and she stood to be a beneficiary in his will.
The story of debt-ridden mother-of-three and night-time sex worker Beverley James. By day, she was meant to care for Harriet Davison, a frail woman she beat to death.
The case of carer Thomas Dunkley, who aided boxer Shaun 'The Guv'nor' Cummins after he became paralysed, and later killed and dismembered his patient.
The case of New York paramedic Paul Novak, who boasted of committing the perfect murder after the dust had settled on the death of his first wife Catherine.