Whittle, a teenage heiress, was kidnapped at gunpoint from her home in Highley, Shropshire, by Donald Neilson; a notorious burglar and murderer known as the Black Panther.

[5] Whittle was driven 65 miles from her home to an underground drainage shaft of a reservoir at Bathpool Park in Kidsgrove, Staffordshire, where she was tethered, naked, upon a narrow platform 54 feet (16 m) below ground by a wire noose affixed around her neck and with a hood placed over her head as Neilson made several unsuccessful attempts to collect a £50,000 ransom from her family over the following days.

[8][9] Donald Neilson was arrested in Mansfield in December 1975 on unrelated charges; he was convicted of Whittle's kidnapping and murder in July 1976 at Oxford Crown Court and sentenced to life imprisonment.

[12] Although from a wealthy family, Lesley did not live an affluent lifestyle, with her inheritance held in trust and Dorothy giving her £20 a week in spending money (the equivalent of approximately £214 as of 2025[update]).

[6] Encountering Lesley asleep in her bed, Neilson shook the teenager's shoulder until she began to awake before placing his hand over her mouth as she opened her eyes to see him pointing a gun at her face.

[6] A mattress, torch and a sleeping bag were already upon the ledge and according to some sources, Neilson gave the naked teenager a flask of soup, a bottle of brandy, a small puzzle, and six paperback books to occupy her time and insulate her against the frigid temperature.

[15] These notes demanded a £50,000 ransom (the equivalent of approximately £536,000 as of 2025[update]) for Lesley's safe return and instructed the family not to contact the police, but to wait for a telephone call at a phone box at the Swan shopping centre in Kidderminster that evening.

[30] On the evening of 15 January, Neilson drove to a car park close to Dudley Zoo with the intention to leave a section of his relayed instructions for Ronald in a phone box.

[30] With Ronald's agreement, Scotland Yard investigators placed a covert listening device beneath his suit in order that he could communicate with officers, who guaranteed him assistance within two minutes should he request it.

"[33] Ronald arrived at Bathpool Park and turned into the service area as instructed, but in the dark he did not see the low wall that edged the railway bridge, and drove to the end of the lane.

He was also eager to maintain the impression to the kidnapper that the Whittle family had not contacted police at any point since Lesley's kidnap and prior to the discovery of the contents of his vehicle.

[41][n 5] Accessed by a vertical ladder, 22 feet (6.7 m) down on the first landing, Detective Constable Philip Maskery discovered a broken police torch from the previous day's search.

Hanging suspended from the ledge of this platform, with her bare feet only 7 inches (180 mm) from the bottom of the shaft, was Lesley's naked and emaciated body, clad only in a pendant necklace her boyfriend had made for her and six silver bangles upon her right wrist.

[43] Upon hearing of the discovery of Lesley's body and the circumstances surrounding her death, Chief Superintendent Robert Booth remarked to the press: "I will get this callous killer if it's the last thing I [ever] do.

[43] Neilson always insisted Lesley accidentally fell to her death in the early hours of 17 January when she stepped aside as he climbed down the ladder to the narrow ledge where he had tethered her following the thwarted ransom delivery.

However, Neilson may not have been present when Lesley died as he may have fled from Bathpool Park on the night of the failed ransom collection, suspecting a police trap after the courting couple drove away from the rendezvous point after he had repeatedly flashed his torch.

[49] Two days after the discovery of Lesley's body, Commander John Morrison of Scotland Yard's homicide division replaced Chief Superintendent Robert Booth as head of the investigation into the kidnapping and murder.

Many fruitful lines of enquiry had already been vigorously pursued under Booth's command, including investigating the origins of the traceable items recovered from the kidnapper's vehicle and at Bathpool Park in addition to conducting a public appeal to trace the Black Panther by playing a secret recording made of the kidnapper talking with Ronald Whittle about delivering the ransom money on 16 January.

[7]: 30 In the spring of 1975, a reenactment of the Black Panther's movements on the dates of the kidnapping was filmed and broadcast nationwide, with the reconstruction using the stolen Morris 1300 recovered at the site of Gerald Smith's shooting.

The actor dressed in similar clothes to the Black Panther, and the footage featured him driving to and standing by telephone boxes used in the kidnapper's ransom trail in addition to walking around Bathpool Park.

The confession was given to DCS Harold Wright, head of Staffordshire CID, and Commander Morrison of Scotland Yard, with the statement hand-written by DCI Walter Boreham.

[56] A search of Neilson's Bradford home revealed numerous items of paraphernalia attesting to both his extensive methodology in planning and executing his burglaries and Lesley's kidnapping, and his fixation with the military.

These included an 'operations' book listing post offices and wealthy homes Neilson had considered targets for future burglaries,[32]: 60  balaclavas, maps, coils of rope, a roll of silver heavy duty tape, radios, torches, knives, jemmies, crossbows, bandoliers containing live rounds, haversacks and a sawn-off shotgun.

[7]: 35 Neilson took the stand in his own defence; he remained in the witness box for nineteen hours—extensively detailing his planning and execution of the kidnapping "operation" and reiterating his claim Lesley's death had been accidental.

[45] Despite the fact Lesley was emaciated by the time of her death—suggesting she had not eaten for well over twenty-four hours before she died—Neilson also claimed he had bought her fish and chips and a copy of Vogue magazine during her confinement in the shaft.

I have no doubts whatsoever in my mind that that's what had compromised the operation: he murdered her because of that police car causing him to panic and he vented his anger on her by pushing her to her death down that shaft, that hellhole of a place of confinement.

Booth remained adamant that, if not for this delay, Ronald would have arrived at the rendezvous with the ransom money before the courting couple parked at the kidnapper's instructed location.

By 2008, Neilson had been transferred to HM Prison Norwich, and had been suffering from motor neurone disease for several years, gradually leaving him unable to use his limbs and requiring him to be spoon-fed.

His appeal was heard at the High Court in London, with Mr Justice Teare ruling on 12 June that he must never be released from prison, saying: "This is a case where the gravity of the applicant's offences justifies a whole life order ...

None of his family members were present at the time of his death, although his daughter did send a thank-you card to prison staff for the care they provided for her father in his final days.