Dr. Harold Shipman, the World's Most Prolific Serial Killer

When toxicologist Julie Evans filed her report on the cause of Ms. Grundy's death, Det. Supt. Postles was astounded.

The morphine level in the dead woman's body was the cause of death.  Not only that, her death would have occurred within three hours of having received the fatal overdose.

Postles later said Shipman's use of the drug was a serious miscalculation. A doctor would surely have known morphine is one of the few poisons that can remain in body tissue for centuries.  Postles observed, "I was surprised... I anticipated that I would have had difficulty if he gave them something in way of poison lost in background substance." He gave insulin, which the body produces naturally, as an example. "It was an unexpected bonus once I had checked that Kathleen Grundy did not take it herself."

Shipman would claim later that the stylish and conservative old lady was a junkie.  Even today psychologists speculate on the possibility that he wanted to be caught.  Otherwise, why would he hand them the typewriter and use a drug so easily traced back to him?  Others believe he saw himself as invincible, believing that, as a doctor, his word would never be questioned.

The detective realized the case went far beyond one death, and the scope of the investigation was broadened immediately.