Moore was born in 1940 and ran cinemas in north Wales, living with his mother until her death in 1994. He was known locally as a businessman and was a familiar figure in the towns where his cinemas were.
Between September and December 1995 he killed four men: Henry Roberts, fifty-six, at his home in Anglesey; Edward Carthy, twenty-eight, whom he met in a Liverpool bar; Keith Randles, forty-nine, a traffic-site watchman; and Anthony Davies, forty, on a beach. He stabbed and mutilated them. He wore black, and he told police he had done it for fun.
He was arrested in December 1995 after Davies's death and convicted at Mold Crown Court in November 1996. The judge described the killings as murders committed for pleasure, and he received four life sentences with a whole life tariff. He is one of a small number of prisoners in England and Wales who will never be released.
His defence attempted to attribute the killings to a lover he called Jason, whom the prosecution said did not exist; the name came from the horror films shown at his cinemas. The jury rejected it.
He is the only serial killer in modern Welsh history, and the case is remembered there for the ordinariness of the man alongside the four months of it.