Role-playing fentanyl killer Luke D'Wit one of most dangerous we've faced, say Essex Police

• ITV News Anglia's Hannah Pettifer reports on how D'Wit manipulated his victims over a number of years

A manipulative killer who murdered a married couple with poison was one of "most dangerous" ever dealt with by police, say officers who are now probing his past in search of previous crimes.

Luke D’Wit, 34, drugged Stephen and Carol Baxter with the strong painkiller fentanyl at their home in Mersea Island, Essex, in April last year. 

Mr Baxter, 61, and his 64-year-old wife were found dead sitting in armchairs in their conservatory on Easter Sunday, 9 April 2023.

On Wednesday, jurors at a trial at Chelmsford Crown Court found the IT worker, of West Mersea, guilty of the murders. 

Essex Police said the “cool, calculated killer” D’Wit went to lengths they had never seen before to plan his crimes and would have gone on to kill again if he was not caught. 

D’Wit, who denied the murders, will be sentenced at a later date. 

'Enjoyed control'

D’Wit worked for and befriended the Baxters and spent years controlling them, with his elaborate plot involving false identities, fake wills and deadly medication.

Det Supt Rob Kirby said the 34-year-old had “planned their deaths meticulously” and “appeared to enjoy control” over the family.

Mr and Mrs Baxter’s daughter Ellie told the trial that D’Wit would come round to their house “every day”, knew the front gate security pin, location of a key safe, and would give medication to Mrs Baxter in the mornings and evenings.

He invented fake support groups and doctors to provide advice on Mrs Baxter's thyroid condition, with audio recordings capturing D’Wit “practising fake voices”. 

Emails from a fake doctor told Mr and Mrs Baxter to drink boiling water, lemon and aspirin tablets and prosecutors suggested this was creating a “concoction [D’Wit] could put something into to kill them off”. 

Two days before Mr Baxter and his wife were discovered dead by their daughter, doorbell camera footage captured D’Wit walking towards the Baxters’ address looking at a phone.

Prosecutors said D’Wit installed a “mobile security surveillance application” on his phone, allowing him to monitor a camera from another device and that he was “watching them die”.

'Convincing statement'

Mr and Mrs Baxter were found dead by their daughter Ellie at their home on Easter Sunday 2023 after she saw that they were "sitting in their armchairs, not moving".

D’Wit went to the scene and spoke to a 999 operator, speculating that “it could be gas”.

Listen to the audio of the 999 recording played in court. Some viewers may find this content distressing

A separate video captured on police bodycam then showed D'Wit telling an officer outside the couple's home that he had become "uneasy" with the lack of communication from them in the days leading up to their deaths.

Luke D'Wit was initially treated as a witness rather than a suspect - watch officers speak to him shortly after discovering the bodies of Carol and Stephen Baxter

Following the discovery of the bodies, he said he gathered all of Mrs Baxter's medication in a box after being asked to do so by the first responder.

"Yeah, they like to know what people take," the officer replied.

"Every morning she takes Levothyroxine [a medicine used to treat an under-active thyroid gland], but sometimes she forgets and she can take it six or seven times," D'Wit added.

Police described the lengthy statement given as “very convincing”. 

The day after their deaths, D'Wit wrote a fake will on his phone in which he made himself the beneficiary and inheritor of their shower mat firm Cazsplash, said prosecutor Tracy Ayling KC.

Police said D’Wit only became a suspect because he was the last to see them and “unusually” avoided the house on the weekend he killed them.

'One of the most dangerous' killers police have seen

D’Wit poisoned the couple with fentanyl, with the sedating antihistamine promethazine also present in Mrs Baxter.

Fentanyl is a synthetic opioid used to treat severe pain that is up to 50 times stronger than heroin, and 100 times stronger than morphine.

Police knew that D’Wit had access to the opioid from a relative who had been prescribed it and a bag found on D’Wit when he was arrested at work contained patches of fentanyl, both opened and unopened. 

Watch the moment Luke D'Wit is arrested at work

Quadruple doses of promethazine were also found, described as “made up pills with four times the amount of promethazine as normal”.

“There can only be one purpose for having these and that’s to fool someone into believing they were taking a proper dose when they were actually taking four times the amount,” said Ms Ayling earlier in the trial.

Det Supt Kirby said that as D’Wit was found with the equipment on his arrest, it suggested that he would have “gone on to kill someone else”. 

He added: “I think D'Wit is one of the most dangerous people I've ever experienced in my police career, and I have absolutely no doubt in my mind that he would have gone on to kill other people."

"It's a truly unbelievable case. The lengths that D'Wit went to to plan what he did and control the Baxters was simply something that I've never seen before."

D'Wit created more than 20 personas, including a doctor supposedly based in the US who would give advice to the couple about their illnesses and suggested treatments.

Det Supt Kirby added: "Carol's behaviour became erratic because we now know she was being poisoned on a regular basis.

"The doctor at one point said that Carol's phone should be removed from her. The doctor also introduced Carol and Stephen to other patients of hers in America.

"Through the digital work that the analysts completed, it was found that all of those people was D'Wit," he said.

"We certainly think that D'Wit's motivation was financial. There was an element that D'Wit enjoyed the control he was exerting over the Baxters and that appears to be a motive for his actions."

Police said they would be continuing to investigate D’Wit’s past to rule out any other crimes he may have committed.

Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know