On the morning of March 21 1984, Hilda Murrell was preparing to make a presentation to the Sizewell B Inquiry, the first public planning investigation into the launch of a new nuclear power plant in the UK.

A lifelong environmentalist, over the previous decade she'd become extremely concerned about hazards posed by nuclear power in both its energized and weaponized forms, and campaigned with ever-increasing fervor against its proliferation.

Hilda's presentation was prepared with support from dissident scientists and activists, and offered expert insight on the risks posed by nuclear power and radioactive waste management.

Concerned attendees sat in the inquiry's public gallery were likely much looking forward to her testimony, while many in the British nuclear industry were conversely no doubt dreading it, for much the same reasons - despite Hilda's age, she was a formidable figure who commanded respect, and whose views demanded consideration.

The presentation would never come to pass. At around noon that day, Hilda's home was broken into and she was abducted - apparently in her own car. The vehicle was later found abandoned in a country lane, five miles outside the town - three days later, her mutilated body was found by police in a copse a field away from her car.

Hilda had been beaten and stabbed multiple times before being left to die from hypothermia sometime later. The resultant police investigation produced no leads or suspects - at least officially - and was widely criticized as negligent and superficial.

Officers concluded Hilda disturbed an individual burglarizing her home, who then attacked and kidnapped her. In December that year, the delayed inquest into Hilda's murder - at which only the doctor who carried out her autopsy, who later had his license revoked, and the local Detective Chief Superintendent, were permitted to give statements - reinforced this narrative, ignoring serious anomalies in the process, such as strong suggestions Hilda's body had been moved after her death.

Alternative theories quickly proliferated among Hilda's friends and family, the media and even members of parliament. Most commonly, it was suggested she was murdered due to her prominent anti-nuclear activities and opposition to the 1982 Falklands War - whether by individuals acting on behalf of the industry, or members of the security services. The latter theory was ardently supported by Labour MP Tam Dalyell, who repeatedly raised the issue in the House of Commons.

"Whoever was in [Hilda's] house had clearly been looking for something. [It] had been carefully searched and her papers gone through in an orderly manner. Her telephone had been cut off in such a way that, although it was dead from inside the house, anyone calling would hear it ringing out. The police agree that is a sophisticated way of doing things - not the actions of a common burglar taking a chance. I am certain persons in Westminster and Whitehall know a great deal more about the violent death of Hilda Murrell than they have so far been prepared to divulge," Dalyell said December 19 1984.

Ever since, the intrepid rose-grower has rarely strayed very far from public consciousness. Her case has been dissected and immortalized in books, documentaries, plays and films, and as of 2018, it remains an enduring mystery, perhaps the most bizarre and baffling murder in the history of 20^th century Britain - despite the conviction in May 2005 of Andrew George for Hilda's abduction and murder.

George, a laborer in Shrewsbury who at the time of her killing was a 16-year-old truant from a foster home who couldn't drive, was arrested June 2003 after a police review uncovered DNA and fingerprint evidence linking him with the crime. At his trial, he admitted being in Hilda's house, but denied abducting or murdering her. The jury didn't believe him, and he was sentenced to life imprisonment with a recommended minimum term of 15 years.

Many, however, do believe George - among them Robert Green, a noteworthy anti-nuclear campaigner in his own right. He believes George – "a petty thief kind to old people" – was unjustly incarcerated, and DNA evidence withheld from the jury would not only likely acquit him, but establish beyond reasonable doubt at least one other male, whom Hilda scratched, and possibly another whose semen was on her cardigan, were involved in her murder.

Robert believes MI5 and/or the nuclear industry, with potential assistance from a private security agency, abducted Hilda and took her to a 'safe house' to interrogate her and retrieve any sensitive information she may have possessed, then identify its sources and neutralize them - but not before permanently silencing and disposing of her.

Chillingly, the former IRA operative later suggested such snatch squads were occasionally housed at Sir John Moore Army Barracks in central Shrewsbury - not far from Hilda's home. A 28^th anniversary meeting in the town yielded yet further troubling revelations. After the meeting, a man said his friend had explosive information to impart, but was too nervous to talk because he was subject to the Official Secrets Act.

He said that early on the morning of March 21 1984, his friend had been helping guard the main gate of RAF Shawbury, not far from where Hilda was found. Four Dutch or Swiss agents who spoke perfect English came out of the base having been flown in. Claiming to be electrical engineers, they were "muscly, fit and scary to look at'" and spent no time in the base where they were supposed to be working. They returned four days later and were flown out. Moreover, he alleged the nearby Sundorne Territorial Army Centre, which was closed on dates coinciding with Hilda's abduction and the discovery of her body, was where she was held.

"My wife Kate was also approached outside the meeting by a man pointing to state involvement in Hilda's murder. Now we have to contend with the possibility she possessed information far more damaging to the Thatcher government than anything we previously knew about, possibly unrelated to the nuclear industry and/or Falklands War. Could this information threaten even the current government? That might explain all the extraordinary attention we continue to experience," Robert told Sputnik.

As a result of his attempts to bring his findings to public attention, Robert has been subjected to concerted harassment and surveillance by security services in both the UK and New Zealand, where he currently lives - a campaign that stepped up significantly when he began researching and writing A Thorn In Their Side, his book about the case.

He and his wife's mail has been frequently opened, damaged, redirected or even lost outright, and their home repeatedly broken in to and monitored from the outside by a variety of vehicles.

In 2008, as Robert and his wife prepared to leave for Europe to research his book, they warned a skeptical house-sitter about this barrage of intrusion - later that night, as the house-sitter returned to the house, he saw a man silhouetted by torchlight through the living room window. When he finally entered the house , there was no sign of forced entry, and nothing had seemingly been taken. Subsequently, the house-sitter noticed a car parked outside the house several times. On the final occasion, when he parked behind it one evening and got out to challenge the driver, the car shot off at high speed.

Some harassment in the UK has been even more sinister. In February 2008, for example, he and his wife were staying at a pub. At 1.30am one night, he and his wife were woken by an intruder trying to unlock their bedroom door - a peep through the keyhole revealed a large tracksuited man. Alerted, the individual fled the scene in an unmarked white van equipped with aerials, which had been parked across the street since they arrived.

Robert isn't alone. He has documented the harassment and even murder of other whistleblowers who spoke out about contentious nuclear issues, or attempted to supply him with sensitive information.

For example, Dr. Rosalie Bertell, an American researcher for the National Cancer Institute, discovered in 1977 low radiation levels caused leukaemia and other health problems. When she spoke out about her findings, she experienced severe harassment, including attempts on her life.

Dr. Patricia Sheehan, an Irish scientist, discovered in the 1980s mothers of children in Dundalk born with Down's syndrome had all been at a boarding school in 1957 when a fire in Windscale in Cumbria, northwest England, released radioactive fallout which was blown across the Irish Sea. In 1994, as she was preparing to present her findings to an inquiry into birth defects at Sellafield, Dr. Sheehan was found dead in her car, her papers missing. The crash was never fully investigated.

Some cases are closely connected with Hilda's. Philip Griffith, whose adopted mother Eileen knew Hilda, phoned Eileen from Brighton soon after the first anniversary of her murder to report he'd overheard men in a pub bragging about how they'd killed her. He was found by a work colleague early the next morning in a park dying of a drug overdose. It took a fortnight for police to inform Eileen - when she identified Philip's body, he had a severe wound on his forehead, as if he'd been hit with a hammer. Investigators dismissed his death as drug-related.

Willie MacRae, a leading radical lawyer, Scottish National Party member and anti-nuclear campaigner - who'd often corresponded with Hilda - was found in 1985 dying at the wheel of his car off a main road in the Western Highlands with two bullet wounds in his head. His smashed wristwatch and papers were found twenty yards from the car, and a gun further away in a stream. His death was officially ruled a suicide, and no inquest was held. It has been confirmed Willie was under surveillance by Special Branch at the time of his death - and like Hilda, was preparing to give evidence at an inquiry into the nuclear industry.

Despite the barrage, Robert is determined to continue his efforts. In October 2017, he submitted a 'victim personal statement' to the UK parole board, having learned George could be paroled May 2018. He drew its attention to the updated 2013 edition of his book, summarized why he believed George was wrongly convicted, and made clear he posed no threat to Hilda's extended family. It would not be until March 2018 that he was informed by his victim liaison officer that George had been refused parole.

A little over three years earlier, documents relating to Hilda's murder were released under the UK's 30-year disclosure rule. Robert inspected and copied the heavily redacted material, files which indicated "extraordinary concern and involvement" in the case at senior government levels, including MI5. He later found out two particular extracts from one file remain closed until January 1 2070. "All this," Robert asks incredulously, "in a murder case where authorities insist a lone teenage truant was responsible?"