Andrew Dawson was born in 1962 in Ormskirk, Lancashire, England.

In August 1981, Dawson, at the age of 19, murdered 91-year-old shopkeeper Henry Walsh in Ormskirk by stabbing him 11 times. He was convicted in 1982 and sentenced to life imprisonment. After serving 17 years, he was released on license in 1999.

Following his release, Dawson struggled to reintegrate into society, facing multiple re-incarcerations between 2003 and 2007 before a final release in 2008. On July 25, 2010, he murdered his neighbor, 66-year-old John David Matthews, in Chaddesden, Derby, by stabbing him multiple times and placing his body in a bathtub filled with bleach to mask the odor. Five days later, on July 30, 2010, Dawson similarly murdered another neighbor, 58-year-old Paul Hancock, using the same method. He was arrested on the same day Matthews' body was discovered.

During the investigation, authorities found a letter in Dawson's apartment signed "Yours, the Angel of Mercy," indicating a possible self-perception as a merciful figure. On July 18, 2011, Dawson was sentenced to life imprisonment with a whole-life order, ensuring he would never be released.