Dr. Harold Shipman

When Dr. Harold Shipman lost his mother, he saw how morphine eased her pain before she passed. Then he became a doctor and used morphine overdoses to kill people, especially rich old ladies, and wrote himself into their wills with forgery. He was eventually caught because it was suspicious that every single one of his patients had him in their will, and that they all died under his care - but he did “inherit” a number of estates and a lot of money before getting caught.