Detectives have closed a review into whether fentanyl murderer Luke D'Wit was a serial killer, the BBC can reveal.

D'Wit, 37, is serving life with a minimum term of 37 years for the murders of Stephen and Carol Baxter who he befriended before poisoning them at their home in West Mersea.

Essex Police examined the deaths of his father and grandfather after his conviction in 2024 and considered bringing new charges against him, although it is unclear what they related to.

"We have consulted with the Crown Prosecution Service (CPS) and at this stage we are not seeking to bring additional prosecutions against Luke D'Wit," it said.

The review was prompted by similarities in the deaths of D'Wit's father Vernon and the Baxters - all of whom were found dead in their armchairs.

Detectives reviewed the oddball killer's past, interviewed people who knew him and carried out "detailed forensic analysis" at his home in West Mersea, where a stash of the powerful synthetic opioid painkiller fentanyl was found.

Having consulted with the CPS, they subsequently closed the investigation after deciding the cost was not justified when considering the lengthy prison sentence already being served by the IT expert.

Carol Baxter, 64, gave D'Wit a job designing a website for her lucrative shower mat business and soon took the loner under her wing.

D'Wit had been viewed by people living on Mersea Island as a pillar of the close-knit community, having volunteered at a soup kitchen and helped with the town carnival.

But in reality, he spent years manipulating Carol before smuggling a lethal dose of fentanyl into health smoothies he made her and husband Stephen, 61, on Good Friday 2023.

The killer, who claimed to be like an "adopted son" to the Baxters, then watched them die via a hidden camera he set up in their five-bedroom house.

Police later found a haul of fentanyl, which had been prescribed to D'Wit's father and stashed "in abundance" after his death. It was stored in a backpack at D'Wit's house.

Det Supt Rob Kirby, who led the original investigation, previously told the BBC he could not rule out the possibility D'Wit had already killed others with the drug.

He described the murderer as "one of the most dangerous men" he had encountered and said he believed there was "absolutely no doubt" he planned to strike again.

An Essex Police spokesman said: "Since D'Wit's sentencing, we have carried out a thorough review of past behaviours and incidents.

"This work has varied from taking witness accounts to carrying out detailed forensic analysis.

"We have consulted with the Crown Prosecution Service and at this stage we are not seeking to bring additional prosecutions against Luke D'Wit."

Police said all involved parties had been consulted about their decision.

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