An IT worker who fatally poisoned a couple with the opioid painkiller fentanyl and rewrote their will has been jailed for a minimum of 37 years.
Stephen Baxter, 61, and his wife Carol, 64, were found dead at their home in West Mersea, Essex, in April 2023.
Luke D’Wit, 34, used fake identities to manipulate the couple before he laced their medication with the drug, a trial at Chelmsford Crown Court heard.
D’Wit, from West Mersea, will serve at least 37 years of a life sentence.
Det Supt Rob Kirby, the head of major crime at Essex Police, said he had “absolutely no doubt” that D’Wit would have committed further murders had he not been caught.
He said the defendant was “one of the most dangerous men” he had seen during his policing career.

The trial heard D’Wit secretly laced the Baxters’ medication with fentanyl and made sure they consumed it when he visited their house in Victory Road on 7 April 2023.
Mr and Mrs Baxter’s daughter, Ellie, found her parents dead in their conservatory when she visited two days later on Easter Sunday.
D’Wit arrived soon after and described himself as a “friend” to a 999 call handler, before calmly giving a false account as Miss Baxter was heard in distress in the background.
Reading her victim impact statement at Chelmsford Crown Court, Miss Baxter described D’Wit as a “man so manipulative he hacked his way into our lives over a decade ago, schemed and thoroughly planned my parents’ demise”.
She said her parents had “looked after Luke”, adding: “They just decided he was lonely, especially after Luke’s dad died. They took him under their wing and would let him join in.”
Describing the moment she found them dead, she said: “I have never known an emotional pain to physically hurt so much.
“It was like my insides were on fire. I screamed and I screamed.”
The defendant first met the Baxters between 2012 and 2013 after he was asked to build a website for their shower mat company, Cazsplash.
The court heard the day after they were found dead, D’Wit rewrote their will so he could seize control of the business.
Tracy Ayling KC, prosecuting, said the murders were the culmination of years of manipulation by D’Wit, mostly focused on Mrs Baxter but also – at times – her daughter.