Premise: A Spanish man who murdered a Welsh couple with a hammer on the island of Fuerteventura has been jailed for 39 years by a court in the Canary Islands. Brian and Tina Johnson were bludgeoned to death by tenant Juan Carmelo Santana, 42, when they tried to collect overdue rent from him in July 2006. Santana was sentenced to 17 years for Mrs Johnson's murder and 22 for the more "brutal" killing of her husband. He was ordered to pay their son Sam £270,000 in a private prosecution.
Hypothesis: Sam was the couple's only child.