The lead suspect in the murder of West Yorkshire teenager Elsie Frost died before police could charge him, an inquest into her death has heard.
Convicted rapist and murderer Peter Pickering, also known as the 'Beast of Wombwell', was close to being charged with Elsie's murder at the time of his death in March last year.
Elsie, 14, was murdered in 1965 after being stabbed to death walking home from a sailing event in Wakefield. The case has never been officially solved and a new inquest into her death is being held following campaigning from her siblings Colin Frost and Anne Cleave, who have called for the case to be looked at again.
The hearing at Wakefield Coroner's Court on Monday heard that Scotland Yard sent a file on Pickering to West Yorkshire Police just days after the "truly ferocious attack" in which Elsie's skull, brain and heart were pierced.
However, the file was returned as the force could not trace him.
Two months later, Ian Spencer was charged with Elsie's murder but cleared of the charge the following year, leaving the case to go cold for nearly 50 years.
Primary suspect Pickering went on to murder 14-year-old Shirley Boldy and kidnap and rape an 18-year-old woman in Barnsley in 1972.
Elsie's sister Anne Cleave told the inquest of her family's anger that the case had been left "in limbo" for decades following Ian Spencer's exoneration in 196.
She told the court: "Pickering's name had already cropped up because a file was sent up from Scotland Yard.
"The outcome of that, of course, is the fact that Pickering goes on to commit other crimes. If things had gone as they should have done in 1965, those events may not have happened and maybe then my sister's case would have come to full fruition."
Mrs Cleave continued: "I've been very angry that nothing happened after Mr Spencer was released. That makes me very angry, nothing happened until Colin and I got things going again after Dad died.
"After March 1966, after Mr Spencer was released and exonerated, that's when things stopped."
The inquest heard that police in Wakefield were sent a file on Pickering from the Metropolitan Police on October 13 1965 - just four days after Elsie was stabbed to death as she walked back from a sailing club event.
On October 25, the force returned the file with a note, which read: "The file in respect of Peter Pickering was forwarded to this office making Pickering a likely suspect.
"Accordingly, extensive inquiries have been made but Pickering has not yet been traced."
The force requested that the Metropolitan Police informed them if Pickering was apprehended.
Following Elsie's family's fight for a fresh review of the case, West Yorkshire Police revealed it had been close to charging Pickering when he died in March 2018, meaning he never faced trial for her murder.
An original inquest into Elsie's death in December 1965 heard that railway fireman Ian Spencer had killed Elsie, although he was later cleared of the charge and the High Court quashed the original inquest's verdict earlier this year.
Lee Spencer, Mr Spencer's son, told the inquest that, despite being formally acquitted of Elsie's murder, his father was repeatedly questioned by police in relation to other crimes.
He also described how his father would make detailed notes following his arrest so he could account for his movements.
Brother Colin Frost, who was five when his sister was murdered, told the inquest that his sister's death had "split the family wide open" and left his parents feeling guilty.
He said: "Elsie's murder split the family wide open and it took a while to get back together."
Mr Frost agreed with coroner Kevin McLoughlin that Elsie's murder had a "truly devastating impact" on the family and said the fact that no-one had been convicted added to the distress.
He said: "The fact that they couldn't get into court to get what we see as the ultimate outcome has added to the distress. Added a huge amount of frustration too."
He added: "We have so many questions going on around, going through our heads. And it's still happening today. Still many questions out there we feel have not been answered."
Mr McLoughlin told the inquest that Elsie was described in statements as a "model child" who was expected to become head girl at school.
Mr Frost added that his older sister was like a mother to him and described how she taught him to tie his shoelaces.
He said: "She carried out that role, in my eyes, perfectly."
The inquest continues.