A "sadistic" teenager from Wirral who tortured and murdered his girlfriend in a frenzied attack has been jailed for at least 22 years.
Adam Lewis, 18, was sentenced to life imprisonment at Liverpool Crown Court for the murder of Hannah Windsor, 17.
Hannah was tied to a tree, sexually assaulted, strangled and attacked with a knife by Lewis, of Fairmead Road, Moreton.
Passing sentence, Mr Justice Holroyde told him: "Only you know what you did to Hannah and in what order you did it. It is, however, clear that you deliberately inflicted cruel injuries upon her which must have caused her immense pain and suffering."
Lewis, who has learning difficulties and a low IQ, showed no emotion as the judge told him the pathologist's report into Hannah's death made "chilling reading".
He added: "Adam Lewis, that was a prolonged, merciless and terrible attack, which must have been agonisingly painful for Hannah Windsor before she died. You must have known what dreadful pain you were causing her."
The judge said Lewis showed "dreadful cruelty" and added: "I am quite sure that your murder of Hannah Windsor involved both a sexual and sadistic element."
Members of Hannah's family sobbed as they followed proceedings from the public gallery.
The judge said: "In every crime of murder, one life is taken but many others are damaged.
"I have read and taken account of statements by both of Hannah's parents. They, and other members of her family and friends, have suffered and will continue to suffer as a result of what you did."