A PATHOLOGIST has told a murder trial a "fatal range" of promethazine was found in a Mersea woman's blood following her death. 

Carol and Stephen Baxter, who lived in Victory Road, West Mersea, were found dead on Easter Sunday on last year.

Luke D’Wit, who had befriended the couple, was arrested in July and stands accused of murdering the couple by poisoning them with lethal doses of fentanyl, a powerful painkiller.

On Tuesday, the prosecution swore in expert witness Dr Matthew Cieka, a forensic pathologist, to support their assertion that D’Wit was responsible for the Baxters' death.

Gazette: Court - the jury has now been sitting at the trial for nine daysCourt - the jury has now been sitting at the trial for nine days (Image: Daniel Rees, Newsquest)

Dr Cieka told the court how there were both undissolved white tablets and fentanyl found in Mr Baxter’s stomach, according to a toxicology report.

He said: “The deceased had fentanyl, a strong opioid painkiller, in his blood.

“He was not prescribed this medication - although it was reported to be in the therapeutic range, the deceased is likely to have had no tolerance to the concentration of this drug.

“If you’ve never taken it before and are naive to it, it’s extremely potent and can cause toxicity at extremely low concentrations.”

When asked by prosecuting barrister, Tracy Ayling KC, whether there was the potential of third-party involvement in relation to Mr Baxter’s death, Dr Cieka replied, “Yes.”

The court then heard there was evidence of both promethazine, which is a type of anti-histamine, as well as fentanyl in Mrs Baxter’s blood following analysis of toxicology results.

Dr Cieka said: “Concentration of promethazine was in the fatal range.

“Fentanyl was not prescribed to the deceased, and although the level in her blood is difficult to interpret, the combined sedative affect of both drugs is deemed to be significant.

Gazette: Defendant - Luke D'Wit was a friend of the Baxters, the court has heardDefendant - Luke D'Wit was a friend of the Baxters, the court has heard (Image: Essex Police)

“The potential for a third party [being involved] had to be explored.”

Dr Cieka added the absence of any fentanyl patches – which is a means by which fentanyl is prescribed – combined with analysis of blood and urine analysis, suggested the fentanyl had been ingested orally.

“It’s difficult to imagine any scenario where two individuals not prescribed fentanyl could accidentally contaminate their food or drink with this drug,” he added.

D'Wit denies the charges.

The trial continues.