The killer geek who watched elderly millionaire couple die on his phone after slipping fentanyl into their drink – and still shared a bedroom with his mum at age of 34

One thing is certain – no one who knew Luke D’Wit had the slightest inkling that a man they described as ‘kind and gentle’ and a ‘boring computer geek’ was capable of one murder, let alone a double killing.

After all, the 34-year-old didn’t drink, barely socialised and spent much of his spare time at his home in West Mersea, Essex, playing computer simulation games that were a world away from the violent ones so often enjoyed by others his age.

Above all else, he appeared entirely disinterested in money, and even spent some of his spare time volunteering for local clubs and charities.

Yet the chilling fact remains that on April 7 last year this same Luke D’Wit slipped a fatal dose of the powerful prescription opioid fentanyl into the drinks of Stephen and Carol Baxter, a kindly and wealthy couple who had befriended the oddball after he began doing IT work for their fitted shower mat firm.

And it is D’Wit who Detective Superintendent Rob Kirby, the head of the Kent and Essex Serious Crime Directorate which investigated the couple’s macabre deaths, this week described as both ‘cold and calculating’ and ‘one of the most dangerous men I have come across.’

So dangerous, indeed, that had he not been convicted, Det Supt Kirby believes he was ripe to offend again. ‘I have absolutely no doubt,’ he added. ‘That had he not been caught he would have gone on to commit further murders.’

How on earth, then, did this apparently mild-mannered website builder morph into a killer so cold-hearted that, as the jury heard, he even positioned a mobile phone at the Baxters’ home to stream live footage from their conservatory to a home security app on one of his own phones?

This allowed him to watch the oblivious couple dying in front of his eyes from the fatal dose of fentanyl he had administered, before sneaking back into the house to remove any incriminating evidence such as contaminated glasses.

He then wrote a codicil to the Baxters’ wills that would make him a director of their company Cazsplash Ltd, ensuring he would be a beneficiary of their extensive savings.

Yet as the Mail can reveal today, some of those who know him believe his motivation may have been even more sinister, rooted in a desire to ‘get one over’ on those who had written him off and commit the ‘perfect crime.’

‘He thought he was cleverer than most people and was sometimes frustrated that friends had moved on to better things,’ one of them told the Mail. ‘It was like he resented that his [anti-social] personality had got in the way.’

Certainly, D’Wit had failed to make much of his life by the time his path crossed with that of the Baxters.

He grew up as an only child with his dustman father Vernon and mother Jan in a cottage in Churchfields, West Mersea, and attended Thomas Lord Audley School in nearby Colchester before studying for a computer technology degree at the University of Essex.

After university, while friends escaped the close-knit community of Mersea Island in Essex for more exciting lives elsewhere, D’Wit drifted between jobs, working for a garden furniture company in Clacton, and later a furniture company in Colchester before, aged 22, setting up a website design company called Stand Out Studios Ltd with a friend.

It was dissolved 17 months later. ‘They designed a logo and that was it. I don’t think they even found any clients,’ one friend who knew D’Wit at the time told the Mail.

‘Luke thought that having his own website development firm was a status symbol… But it was never a proper company.’

His domestic life was barely more dynamic, with one friend revealing that as his contemporaries got into serious relationships and bought their own houses, the quietly spoken D’Wit remained at the family home with his mother – even, astonishingly, sharing a bedroom with her, with blue sheets for his bed and pink for hers.

‘He was definitely a bit of a mummy’s boy and a home boy,’ D’Wit’s former best friend, who did not want to be named, confided this week. ‘He did not seem to have any ambition and he never really progressed with his life.’

That included his social life: Uninterested in drinking culture, he eschewed the pubs and clubs popular with his peers and seemed little interested in romantic relationships.

‘A lot of us thought he was asexual because he never showed any interest in girls, or guys,’ the friend added. ‘He was into fashion or how he looked. He never had any massive desires for a load of money, or cars or anything else.’

The one thing that did interest the thickset, curly-haired D’Wit was an ongoing passion for IT which, by his mid-twenties, led to him becoming involved in designing and managing websites for local businesses.

He used his skills to help others, creating a Facebook page for the Mersea Island Lions Club – a community group that helps the ‘less fortunate’ in the area – as well as doing website work for the charity’s annual road run event.

D’Wit’s work with local organisations included voluntary work for the Mersea Carnival.

Heidi Cornish, a character witness for the defence, also told the court he had helped at a soup kitchen, adding: ‘He loved to be involved where people need help.’

But it was his IT skills that brought him to the attention of Mr and Mrs Baxter around ten years ago.

At the time the couple had just moved to the area from London and were working hard to promote Cazsplash Ltd, which they had launched in 2012.

A former adult educator, Carol Baxter had come up with the idea for bathroom mats that fit around curved or corner shower units and held the intellectual property rights to those. The company also sold matching towel sets.

Her husband, whom she married in 2000, was a fellow director of Cazsplash, as well as being a senior executive with multi-million-pound international property firm Jonas Lang LaSalle, which has its headquarters in Chicago.

The couple had two children together, a daughter Ellie, and a son, Harry, while Carol also had two children from a previous relationship.

They enjoyed the fruits of their success, with a five-bedroom £1million home.

Perhaps D’Wit had his eye on all this from the start or perhaps that was an idea that developed later. Either way, over time he inveigled his way into the couple’s lives to such an extent that some neighbours mistakenly thought he was a carer for Carol, who had an auto-immune condition.

He was certainly trusted enough by the mother-of-four to assist her with her medication, as well as making the couple ‘disgusting’ smoothies that he said was for the benefit of their health.

It was via these smoothies that, the prosecution suggested, D’Wit administered his fatal dose of fentanyl.

‘It’s difficult to imagine any scenario where two individuals who are not prescribed fentanyl could accidentally contaminate their food with this drug,’ prosecutor Tracy Ayling KC told the jury.

D’Wit’s IT skills also enabled him to create fake online personas to ‘manipulate’ the family, among them bogus doctors.

One called ‘Andrea Bowden’ was based in Florida and gave helpful advice on alternative treatments for Mrs Baxter’s thyroid condition. Conveniently, ‘Andrea’ suggested limiting contact with the couple’s children.

The defendant claimed these inventions were masterminded by Stephen Baxter to encourage his wife to take her medication.

Mr Baxter, of course, was no longer around to defend himself. But in any case D’Wit’s ploy was flawed because there were so many responses to the bogus experts from an obviously ignorant Mr Baxter that it was clear he had no idea they didn’t exist.

Meanwhile, the jury were played a sinister recording in which D’Wit could be heard practising the voice of one of the false identities he had fabricated, this creation had to speak to Mrs Baxter.

Using a high-pitched voice, he said: ‘Hi Carol, it’s Jenny. It’s Cheryl’s sister… Yes, oh, so nice to finally speak to you after all these messages we’ve been doing.’

In court, D’Wit insisted he had been practising this in order to cheer Carol up.

Another disturbing detail uncovered by detectives was that D’Wit told the family he had bone cancer and was having scans.

They assumed this was in order to get the Baxters’ sympathy but it was a claim that was demolished in court where it emerged no hospitals had a record of him receiving treatment.

That D’Wit’s relationship with the unwitting Baxters was based on a number of lies was clear.

Even so, quite when he began to formulate the plan to murder them is unknown – although in court the jury learned that, in a curious twist, a 17mm metal tack had been found in Mrs Baxter’s digestive system in 2022 after she complained of pain.

The same tacks would later be found at D’Wit’s house. The jury was told to ‘consider how the tack got inside her’.

Perhaps D’Wit feared time was running out: At one point, the court learned, the Baxters appeared to tire of D’Wit’s almost permanent presence at their house and began to leave a box outside the front door so he could drop things off without going in.

According to Ellie they had even discussed sacking D’Wit.

Yet he managed to ingratiate himself further, running shopping errands for the couple and taking Mrs Baxter to West Mersea’s Flow Performance gym where they did fitness classes together. D’Wit, who had been overweight, shed several stone in this period.

Then, in April 2023, Luke D’Wit took the calculated decision to administer a deadly dose of fentanyl to the couple who had placed so much trust in him.

Two days later, in a scene fit for a horror film, their bodies – sitting in their favourite armchairs in the conservatory of their home – were found by a hysterical Ellie.

Given the apparent lack of suspicious circumstances, detectives initially suspected carbon monoxide poisoning.

It was only when, weeks later, tests revealed fentanyl in the couple’s systems that a murder investigation was launched – with Ellie and her partner, Marcus Young, among the initial suspects.

Mercifully, detectives soon concluded they had had no part in the deaths, although Ellie still had to endure cross-examination in court, where she emotionally told the jury: ‘All I’m guilty of is loving my parents.’

Detectives’ sole attention was now on D’Wit, who had made a point of telling officers he was ‘almost like a son’ to his victims and in court described himself ‘literally running’ to the Baxters’ house when Ellie told him they had died.

He certainly had the means to commit the appalling crime: A search of his home five minutes away from the Baxters’ revealed an ample supply of fentanyl which had been used by his father, who died of cancer in 2021.

A makeshift pestle and mortar was also discovered, which may have been used to grind it up, along with other substances his victims unwittingly ingested, such as fatal levels of an antihistamine found in Mrs Baxter’s body.

Some of Carol Baxter’s jewellery was also found behind a sofa at his home.

Yet despite the verdict and the unfolding evidence in court of D’Wit’s dark side, there remains a sense of profound disbelief among those who know him that the man they always felt could not hurt a fly had been convicted of such a cruel and callous crime.

‘I was out walking my dog when my mum called me to say he had been charged, and I thought it must have been a different Luke D’Wit. I checked his address to convince myself it was really him,’ his ex-best friend said. ‘What came out in court was just shocking. I always thought he didn’t have an aggressive bone in his body.’

‘He just looked like your average computer geek,’ a neighbour of the Baxters added: ‘I still can’t believe that he did these murders. I just don’t see how he had it in him.’

As we have seen, tragically he did – with fatal and devastating consequences.