It is one of Britain's longest running unsolved murder cases. The Yorkshire Post looks back at the murder of Wakefield schoolgirl Elsie Frost
Who is Elsie Frost?
Elsie lived with her family at 87 Manor Haigh Road, a semi-detached house in Lupset.
She was an ordinary schoolgirl and very close to her parents and siblings. Her older sister Anne described Elsie as "highly intelligent" and previously recalled how she would always play the teacher or doctor in games at home.
Growing up and in her early teenage years, Elsie had a keen interest in religion. She also loved The Sound of Music and could be often heard singing the soundtrack from the film.
Events leading up to her murder
On the day of her murder - October 9, 1965 - Elsie had lunch with Anne, and afterwards had headed to a sailing event at Horbury Lagoon. The old water-filled gravel pit, located on the edge of Wakefield, was popular with youths in the area.
Elsie had helped moor the boats, before collecting her bag to return home.
She was dressed in a yellow cardigan, printed skirt, red anorak and was wearing a brand new pair of leather shoes.
She chose to walk along the canal towpath as she had promised her mum she would not spoil her new shows by traipsing through the mud.
What happened to Elsie?
The schoolgirl was attacked from behind and stabbed to death in a railway tunnel next to a canal towpath.
She was set upon and stabbed five times from behind in a frenzied attack: twice in the back, twice in the head, once through the hand as she tried in vain to defend herself.
Despite her appalling injuries, Elsie managed to stagger out of the tunnel and collapsed finally at the foot of the steps – which lead up from the canal towpath to a grassy verge above. Her body was found at 4.15pm by a dog walker.
The police investigation and first inquest
A massive inquiry saw more than 12,000 men interviewed and a 33-year-old local man was named by the coroner as the teenager's killer.
However, when the case reached criminal court it was immediately thrown out for a lack of evidence and nobody else was ever charged in connection with the killing.
Police reopened the case in 2015 following a high profile campaign by Elsie's brother and and sister, Colin Frost and Anne Cleave.
Mr Frost said that Elsie's parents had died "with a huge amount of guilt" and without ever seeing justice.
Who is Peter Pickering?
Peter Pickering, a sex offender known as the "Beast of Wombwell" was arrested in 2016 and interviewed over two years in the investigation into Elsie's murder.
Pickering, died on March 24, 2018, at the age of 80. He had been detained under a hospital order since 1972 for the manslaughter of 14-year-old Shirley Boldy, who he admitted abducting, raping and then killing in Barnsley.
His death came five days after he was convicted of raping an 18-year-old woman, now in her 60s, weeks before Shirley's death.
Detective Superintendent Nick Wallen, of West Yorkshire Police, said at the time: "We can now formally confirm that Peter Pickering was the man we arrested and interviewed over the last two years as part of the renewed investigation into the murder of 14-year-old schoolgirl Elsie Frost in Wakefield in 1965.
"We strongly suspected that Peter Pickering was responsible for her murder. We had been liaising with the Crown Prosecution Service and it was our expectation that Pickering would be charged in due course."
Her family's battle for justice
In October, last year Elsie's siblings Colin Frost and Anne Cleave, kick-started a legal drive for a new inquest into her death so the public can finally learn the truth about what happened and the family can get “closure”.
Along with legal representatives, will appear at the Royal Courts of Justice on Tuesday to ask the court to consider their application to have the original inquest into Elsie's death quashed and a fresh inquest ordered.