Fentanyl poisoning: The 'nerdy weird' killer who murdered an Essex couple

Stephen and Carol Baxter were discovered unresponsive at their seaside home in April

Luke D'Wit volunteered at a soup kitchen, helped with a town carnival and appeared willing and ready to assist anyone who needed it. In reality, the computer science graduate was a cold, calculating murderer described by a senior police officer as "one of the most dangerous men" he had ever dealt with. How was he caught?

Luke D'Wit went to elaborate lengths to win the trust of Stephen and Carol Baxter.

He used fake personalities to trick them into taking medication and visited their home so frequently that it came across as "nerdy weird", their daughter said.

It was all part of his ruse that would ultimately see him poison the couple with fentanyl, before rewriting their wills to make himself a major beneficiary.

It was just before 20:00 BST on 7 April 2023 when D'Wit double-locked the front door of Mr and Mrs Baxter's house on West Mersea, Essex, and began the short walk home.

D'Wit planned to settle in for the night and watch crime drama Beyond Paradise at the home he shared with his mum.

A CCTV camera on the Baxters' house showed him leaving the property after administering lethal doses of fentanyl

What his mum did not know was that the previous night, her son had poisoned the Baxters by administering lethal doses of the opioid painkiller fentanyl into their medication.

Mr Baxter, 61, and Mrs Baxter, 64, were slowly dying in their armchairs. The next day, they would be found dead by their daughter, Ellie.

The day after administering the fatal doses, D'Wit calmly took his mother out for breakfast and an ice cream.

The 34-year-old was on Wednesday found guilty of murdering the couple and is awaiting sentence.

'He was always there'

D'Wit appeared to be a friendly member of the close-knit island community who gave his time to helping others.

A freelance website designer, he had grown close to the Baxters after building a site for their shower mat business, Cazsplash.

Heidi Cornish, who met D'Wit at a meeting of the Mersea carnival association, told the murder trial he "loves to be involved where people need help".

"He has a good sense of what's right and wrong," she added.

And so it made sense that D'Wit, who kept Mrs Baxter company on walks and helped her take her medication, would run to the family house in Victory Road after they were found dead.

"I need to check on them," he told a police officer at the scene. "I always pop in."

Kate Dawson, a good friend of the Baxters, says his presence in and around the house - even after their deaths - was not unusual.

"He was never rude but just very odd, an odd character. He wouldn't say a lot but was always there, always," she explains.

"He'd just be sitting around having a cup of tea with them but he was always there."

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The trial at Chelmsford Crown Court was told D'Wit's frequent visits over the years were far from friendly. He had sinister intentions and a plot of calculated manipulation was unfolding.

After the bodies were discovered, it was the catalyst for the next stage - to plant a fake will he had created in the house, giving him control of the Baxters' business.

"In hindsight, there's a lot of things that add up," Ms Dawson says. "But at the time I wouldn't have even thought about it."

Ellie Baxter said her parents were looking forward to enjoying life post-retirement

Cocktails of drugs and poison

During the trial, the court heard D'Wit first met the Baxters sometime around 2012 or 2013 and became more involved in their lives over the years.

Mrs Baxter was suffering with the thyroid condition Hashimoto's and her mental state was deteriorating.

According to daughter Ellie, the autoimmune disorder was making her mum "do silly things".

So when a doctor from the United States offered her services and access to a wide network of fellow sufferers, it seemed to be the reassurance Mrs Baxter needed.

The only problem was that neither Dr Andrea Bowden nor the other sufferers were real. They were created by D'Wit to manipulate Mrs Baxter and to trick her into distancing herself from her family.

Police and paramedics were called to the Baxters' home on Victory Road on Easter Sunday 2023

The couple were found dead in the conservatory by their daughter

D'Wit, the trial heard, would help Mrs Baxter by making her smoothies that he claimed were rich in health benefits.

But those smoothies were, in fact, cocktails of drugs and potions that were making her far more unwell than she already was.

And during a hospital scan Mrs Baxter had for a stomach pain, a metal tack inside a medicine capsule was found in her system. Those same tacks would later be found at D'Wit's house.

On the night of 7 April, D'Wit administered fatal doses of fentanyl to the Baxters in what they thought was their medication.

'Our dear friend Luke'

The day after the Baxters were found dead, a new will was drawn up in their name. It detailed how their "dear friend Luke D'Wit" would be made the director and person with significant control of Cazsplash should they die.

It would be a key piece of evidence in bringing him down.

D'Wit created a will the day after the Baxters were found dead in an attempt to seize control of Cazsplash

When police visited D'Wit's home in July 2023, they found 80 electronic devices. Many had been used to communicate with the Baxters while posing as the fake personalities.

One even had images of the couple dead in their armchairs, taken by a hidden camera he had watched them die on.

And a bag found in his bedroom contained fentanyl patches, medication capsules and metal tacks.

But why would a murderer keep his weapons out in the open? Det Supt Rob Kirby, head of major crime at Essex Police, believes he was planning to strike again.

Det Supt Rob Kirby led tributes to Mr and Mrs Baxter alongside their children, Ellie and Harry

"He is, without doubt, one of the most dangerous men I have ever experienced in my policing career," the officer says.

"He fooled everyone. He befriended people, came across as a very amenable, helpful person.

"But in the background he was a cool, calculated killer who spent years planning the demise of Carol and Stephen Baxter.

"I have absolutely no doubt that had he not been caught, he would have gone on to commit further murders."

D'Wit was arrested at an office he was renting on the University of Essex's campus in Colchester and taken into custody in Chelmsford.

During his trial he gave evidence from a wheelchair, which prosecutor Tracy Ayling KC said was unnecessary and simply an attempt to attract sympathy from the jury.

"D'Wit's downfall was the arrogance that existed within him," Mr Kirby adds.

"He didn't cover his tracks properly and he was deluded in thinking he could use fentanyl to kill two people, and that wouldn't be found to be suspicious.

"Unfortunately for D'Wit, the trail of fentanyl led straight back to him."

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