A man has been jailed for life for murdering his teenage niece in woodland and violating and burning her body.
Louise Smith, 16, was found dead at Havant Thicket, Hampshire, on 21 May - 13 days after she went missing.
Her uncle Shane Mays, 30, was previously found guilty of murder by a jury at Winchester Crown Court.
Imposing a minimum term of 25 years, the judge, Mrs Justice May, said he had committed "the most gross abuse of trust".
Louise went to live with her aunt and Mays, who was her uncle through marriage, in late April after an argument with her mother.
Mays "flirted" with the "anxious and vulnerable" teenager, including by tickling her feet in a video found on her phone, his trial was told.
The defendant, who had admitted manslaughter, told the jury the teenager lured him to woods to "bond" with him.
Giving evidence, Mays said he became enraged when she hit him with a stick during an argument over drugs.
He told the court he did not know how many times he punched her as she lay on the ground, only stopping when he heard her moaning.
The defendant, of Ringwood House, Leigh Park, said someone else must have later interfered with and burned her body.
Louise suffered "repeated, heavy blows" to the head but the cause of death could not be determined due to the fire, the jury was told.
Mays, who was assessed by a psychologist as having an extremely low IQ of 63, said he forgot what he had done until he was in prison on remand in June.
In a victim personal statement read out in court, Louise's mother Rebbecca Cooper said her "strong-willed, happy, smiley" daughter had "the whole world to look forward to".
Addressing Mays, she said: "You killed her in such a traumatic way and what you did afterwards is beyond words. You are a monster...
"You damaged her so bad that I didn't have a chance to say goodbye, hold her hand or even kiss her. I will never forgive you for this."
A statement from the teenager's father, Bradley Smith, said he was "tortured by nightmares" and felt he might "never recover".
Rejecting a whole life term for Mays, the judge said she could not be sure that the murder was "sexually motivated".
"Shane Mays was in a position of trust in relation to Louise; theirs was like a father-daughter relationship," she said.
"That being, he committed the most gross abuse of trust."
She added: "Louise had all her life before her. Her death was bleak, dreadfully so... She was grotesquely and cruelly injured and her body defiled."
Det Insp Adam Edwards, of Hampshire Constabulary, said: "Mays has shown no remorse throughout this case, and has lied to police in a bid to deflect any blame for Louise's murder away from himself.
"I am pleased that the jury were able to see through these lies."
Hampshire Safeguarding Children Partnership said it was reviewing how authorities had cared for Louise, who had an allocated social worker.