This article originally appeared on VICE UK.
When Detective Sergeant Steve Fulcher heard that taxi driver Christopher Halliwell—the lead suspect in the disappearance of Sian O'Callaghan five days earlier—had refused to tell officers anything during his arrest, he made a decision that, in a cop show, would be described as "not doing things by the book." In the real world, the Independent Police Complaints Commission later described Fulcher's actions as a "catastrophic" breach of the Police and Criminal Evidence Act—an official act of Parliament that outlines basic codes for officers to follow, including illegal searches and seizures and a suspect's right to an attorney.
While officers were driving Halliwell from the scene of his arrest, in an grocery store parking lot, to Gablecross police station in Swindon, England, Fulcher called them and told them to instead take the suspect to Barbury Castle, an earthwork from sixth century BC. Fulcher met Halliwell on the wind-swept hilltop at 12:11 PM on Thursday, March 24, 2011. He led him 50 yards away from the officers and their police cars to talk. Their conversation was recorded by the only other person there, a civilian notetaker:
Fulcher: "Are you going to tell me where Sian is?"
Halliwell: "I don't know anything."
Fulcher: "Are you going to show me where Sian is? What's going to happen, if you tell us where Sian is—that whatever you will be portrayed—you would have done the right thing."
Halliwell: "I want to go to the station."
Fulcher: "Are you prepared to tell me where Sian is?"
Halliwell: "You think I did it."
Fulcher: "I know you did it."
Halliwell: "Can I go to the station?"
Fulcher: "You can go to the station. What will happen is that you will be vilified. If you tell me where Sian is, you would have done the right thing."
Halliwell: "I want to speak to a solicitor."
Fulcher: "You are being given an opportunity to tell me where Sian is. In one hour's time, you will be in the press."
Halliwell: "I want to speak to a lawyer."
Fulcher: "You will speak to a lawyer. I'm giving you an opportunity to tell me where Sian is, before the media gets a hold of the story. Tell me where Sian is."
Long minutes of silence passed. Finally, Halliwell said: "Have you got a car? We'll go."
The previous Friday, 22-year-old Sian O'Callaghan had gone out with her friends and ended up at Suju, a nightclub in Swindon. She left alone in the early hours of Saturday morning, at 2:52 AM, but didn't have far to go. The flat where she lived with her boyfriend, Kevin Reape, was only about a ten-minute walk from the nightclub.
When she still wasn't home at 3:24 AM, her boyfriend sent her a text. There was no reply. When he still hadn't heard from her at 9:45 AM, he contacted the police to report her missing.
"He used to ask me about killing. He said, 'How many people do you need to kill before you become a serial killer?'"
On Sunday, the Wiltshire police put out a public appeal for information. Their analysis had shown that when her phone received the text at 3:24 AM it was somewhere in Savernake Forest—about 12 miles outside of Swindon. To have traveled that far in half an hour, they realized she must have been taken by car. It was at this point that Detective Fulcher (who declined to be interviewed for this article as he's currently in discussions about the serialization of his forthcoming book) was put in charge of the case. He was still hopeful that O'Callaghan might be found alive.
By Tuesday, around 400 members of the public joined the police in their search of Savernake Forest. The following day, police announced that further analysis of O'Callaghan's cellphone signals had led them to the identification of certain "hot spots" to be investigated, and they asked the public to allow the police to search them alone. Fulcher made a statement that the investigation was moving at a "rapid pace" and that "significant lines of inquiry" were being developed. One of the people interviewed that day was 47-year-old taxi driver Christopher Halliwell.
Halliwell was already being treated as a lead suspect, but Fulcher decided to allow him to "run." The cabbie didn't know, but police surveillance teams were watching him, hoping he might lead them to O'Callaghan. Instead, they watched him go to his local drug store to buy enough over-the-counter painkillers to kill himself. Now considered a suicide risk, at 11:05 AM on Thursday, police officers approached him in a grocery store's parking lot as he was picking up a passenger and wrestled him to the ground. He told them nothing during an "urgent" interview, and Fulcher chose to redirect the policemen to Barbury Castle.
Following their hilltop conversation, Halliwell directed Fulcher to a spot 20 miles farther north, near the Uffington White Horse, a prehistoric hill figure created from deep trenches filled with crushed white chalk. He couldn't find the exact spot, but police officers put up markers. Later that day, they'd find Sian O'Callaghan's body there.
When Fulcher told Halliwell he would be handing him over to a constable who would arrest him for murder, Halliwell told him: "You and me need to have a chat."
Once more, Fulcher and Halliwell walked away from the officers to speak privately. Fulcher gave Halliwell a cigarette. Halliwell said: "Do you want another one?"
Getting back in a car, Halliwell led Fulcher and a couple of police officers to another spot around 45 minutes away. During the drive, Halliwell became emotional. "Normal people don't go around killing each other," he said.
Eventually they arrived at a country lane near Gloucestershire. Climbing over a dip in a drystone wall and then counting out his steps into the field, Halliwell arrived at a spot where he said he'd buried a prostitute from Swindon years earlier. In the coming days, police would discover the remains of Becky Godden-Edwards, who had last been seen in December 2002.
Police then took Halliwell back to the station. They processed him and allowed him to speak to a lawyer. When Fulcher next spoke to him, in a formal interview setting, Halliwell's answers were simply: "No comment."
"His favorite book was about the Moors Murders, with a picture of Myra Hindley on the front."
This was not Halliwell's first arrest. Born in 1964, he'd burgled houses as a young man and served time in prison during the 1980s. Ernest Springer, who was a cell mate of Halliwell's at Dartmoor Prison during this time, has claimed that even back then Halliwell was attracted to the idea of becoming a serial killer.
Police involved in the the Sian O'Callaghan case interviewed Springer, and he also told the Sun: "He used to ask me about killing. He said, 'How many people do you need to kill before you become a serial killer?' He just had a thing about them. He wanted people to be proud of him or an area to be afraid of him. Don't ask me why, but that's what he wanted to be. He used to get this magazine called True Detective, with stories about people getting murdered. His favorite book was about the Moors Murders, with a picture of Myra Hindley on the front."
However, after coming out of prison, Halliwell built an ordinary-looking life for himself. He lived with his partner and her three daughters in a suburban semi in Swindon and had three children of his own from a previous marriage. Fellow minicab driver Neil Barnett told the Sun that Halliwell was a "real nice bloke—a genuine bloke, a normal run-of-the-mill bloke. I've got two daughters [and] I would have trusted them in his car."
On the of May 31, 2012, Halliwell appeared in court for a plea hearing. Despite previously confessing to Fulcher and leading police to her body, Halliwell pleaded not guilty to the charge of murdering Sian O'Callaghan.
A few months earlier, in January, the consequences of Fulcher's decision not to do things by the book had become clear. The High Court judge, Laura Cox, had ruled that Halliwell's confession was inadmissible in court as Fulcher had failed to allow him to seek advice from a lawyer or read him his rights. Justice Cox described his breaches of the Police and Criminal Evidence Act 1984 and police codes as "wholesale and irretrievable."
Thanks to DNA evidence linking Halliwell to O'Callaghan, the police pushed ahead with the case. On October 19, 2012, Halliwell appeared at Bristol Crown Court and changed his plea to guilty. He was sentenced to life imprisonment with a minimum of 25 years.
However, as a result of Justice Cox's ruling, the second case—over the murder of Becky Godden-Edwards—collapsed. It took police four years to rebuild the case. Halliwell was formally charged with murder again on March 30, 2016. He entered a plea of not guilty on June 9, but a jury found him guilty three months later. Halliwell received a "full life sentence," meaning he will die in prison. This is a rare sentence, used only about 100 times since it was introduced in 1983, and previously handed down to the likes of notorious serial killers such as Peter Sutcliffe, Ian Brady, and Myra Hindley.
The way Detective Steve Fulcher acted during his interrogation of Christopher Halliwell is known as "noble cause corruption." Fulcher has argued that while he knew regulations said he should have reminded the suspect of his right to remain silent and given him access to a lawyer, he acted in the belief that Sian O'Callaghan might still be alive and could have been saved. Following Halliwell's second conviction in 2016, Fulcher said in a statement: "As the law stands, the expectation was that I should have prioritized Halliwell's right to silence and legal protection over Sian O'Callaghan's right to life. I remain convinced that the action that I took in allowing Halliwell to take me to the bodies of both Sian and Becky was the right and moral thing to do."
However, the Police and Criminal Evidence Act is designed as a blanket rule to protect all interviewees who come into contact with the police, especially those who are vulnerable or easily led. Fulcher never read Halliwell his rights, even after it became clear he was dealing with a murder rather than a kidnapping, and his decision to throw out the rulebook almost derailed both cases. He was later found to have committed misconduct and given a final written warning. He resigned from the police and went to work as a security and policing guard in Somalia.
Fulcher still believes, as other detectives do, that Halliwell may have killed again. Detective Sean Memory, who was the the senior investigating officer in the Godden-Edwards case, told BBC Radio 4 last September: "I'm definitely concerned. We know that Becky died in 2003 and Sian in 2011. What I don't understand is why there is that gap and how he can turn from a mild-mannered taxi driver taking young vulnerable women home, and on other occasions turn into a killer."
Investigations have continued into Halliwell's past and possible other murders. However, earlier this month, a ten-day forensic search of Halliwell's home in Swindon, which included digging up his gardens and searching garages, ended with no items of "significant interest" found.
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