Elsie Frost had spent the afternoon at Snapethorpe School’s sailing club on Horbury Lagoon, a lake next to the Calder and Hebble canal. When Elsie and her friends left between 3:50 pm and 4:00 pm, she took a different route to the others, avoiding the canal towpath to prevent her new shoes getting muddy. She was attacked whilst walking underneath the railway line that runs between Wakefield Kirkgate and Horbury. Elsie was stabbed five times; twice in the head, once in the hand and twice in the back, with one of the knife wounds piercing her heart, which killed her. The wound in her hand, led the police to believe that it was sustained whilst trying to defend herself. The post-mortem showed that Elsie had died of shock and blood loss. Elsie Frost made it through the underpass and collapsed at the bottom of the ABC steps, as they are known locally (because there are 26 of them). She was found at 4:15 pm by a man who was out walking with his 3 and 5 year old children. Over 1,200 written statements were taken down, four hundred people who lived within a 0.25 mi (0.40 km) radius of the murder scene were traced and had their movements checked, over 12,000 men were interviewed and a large number of knives of local residents were examined. Despite an intensive police enquiry that was coupled with national coverage (the manhunt was the biggest that the city of Wakefield had ever seen), the police were unable to establish a motive for the crime or indeed, if Elsie Frost was the intended victim or a passerby who the worst had happened to. The manhunt was later expanded to include the army and also involved the use of metal detectors to try and find the murder weapon.

Pressure from Elsie’s brother and sister (Colin Frost and Anne Cleave) and coverage of the killing on an investigative BBC Radio 4 programme, prompted West Yorkshire Police to re-open the case in 2015, 50 years after the killing. Colin Frost and Anne Cleave had unearthed new evidence which they took to the police. The new investigation produced 100 lines of enquiry, a response that the police found encouraging. The Major Investigation Review team is staffed by serving officers as well as civilians, most of whom are retired detectives. The review team disclosed that most of the original files from 1965 had been destroyed. After the programme was aired on Radio 4, several listeners gave accounts of what they had seen leading to fresh evidence and new theories. Members of the public submitted Freedom of Information requests to The National Archives for the murder files, which were not due to be opened until 2030 and 2060. The requests were denied on the grounds that the police files name other suspected individuals other than the one man sent to trial in 1966; the release into the public domain of this information may harm any future criminal proceedings. It also notes that the files contain post-mortem images and reports which could be distressing for the immediate family. It was revealed during the investigation by Radio 4, that Elsie’s clothes had been returned to the family and then destroyed. This effectively ended any hope of DNA retrieval.

There have been other suspects and theories; one was that Elsie had stumbled across two men engaged in a homosexual act (homosexuality was illegal in Britain up until 1967). Another witness has described seeing a man in his mid-twenties, dressed in white overalls and on a bike. This led to suggestions that the man, who could be a witness, was a butcher’s delivery boy or an abattoir worker. Another theory was that Elsie Frost was meeting up with someone in the days before her death, possibly a boyfriend. Elsie’s father had said that the night before the killing, she went to Balne Lane Youth Club in her best clothes, rather than her normal attire and she had asked to stay later. Another lead was proffered by a schoolfriend of Elsie’s, who, as a nurse, had heard of a third-hand account of a man confessing in hospital to being her killer. This tied in with the homosexual act angle as the man apparently confessed to that taking place and being the reason behind Elsie’s death. Whilst this new information was forwarded to the police, it is unreliable because of its third-hand nature and the man was under the influence of drugs when he made his confession. On 27 September 2016, it was announced that Thames Valley Police had arrested a 78 year old man in connection with Elsie’s death. It was revealed on the 29 September 2016, that the man had been bailed after his arrest.