A man who strangled the 17-year-old daughter of a police detective before dumping her body in woodland has pleaded guilty to murder.
Georgia Williams went missing from her home in Wellington, Shropshire, on 26 May.
Her body was found off the Nant-y-Garth pass near Wrexham four days later.
Jamie Reynolds, 23, fled to Scotland after the killing and was arrested at a hotel in Glasgow. He will be sentenced on 19 December.
Prosecutor David Crigman told the judge, Mr Justice Wilkie, he would have to view "distressing photographic material" relevant to the case before passing sentence.
He said further material relating to photos posted on the internet by other "innocent girls" and examples of extreme pornography also formed part of the evidence.
Mr Justice Wilkie remanded Reynolds in custody until 19 December pending further psychiatric reports.
He said he would have to consider whether a whole-life term was an appropriate sentence.
Georgia's parents and her sister Scarlett were in court to hear the plea.
'Caring, kind and generous'
In a statement, Georgia's father, Stephen, a detective constable with the West Mercia force, said Reynolds's admission gave his family "no satisfaction at all".
"The pain we feel is as raw now as it was when our beautiful Georgia was taken from us back in May," he said.
"We will never ever be able to make any sense of what happened, or why it happened to a young woman as caring, kind and generous as our Georgia."
Supt Adrian McGee, from West Mercia Police, confirmed that Georgia was killed at Reynolds' home in Wellington.
He said the guilty plea was "important" to spare Miss Williams's family from "the further trauma of a full trial".
Mr McGee added: "We know the plea does nothing to ease their pain but hopefully it will help them begin to move forward with their lives once sentence is passed."
Initially, the case was a missing persons inquiry and police hoped to find Georgia alive.
She was last seen at the family home on 26 May and was reported missing two days later, as her family thought she had been staying with friends.
The following day Reynolds was arrested in a Glasgow hotel.
He was first questioned on suspicion of kidnap, but was later charged with Georgia's murder - on the same day police discovered the teenager's body.
After tracking the journey Reynolds' van took on the way from Wellington to Glasgow, police focused their search around the Nant-y-Garth Pass, near Ruthin, in North Wales.
It took four days to confirm the body was that of Georgia, She was identified by her dental records.
Speaking after Monday's hearing, Mr McGee thanked all those witnesses who came forward to help them piece together Reynolds' journey.