FENTANYL patches with identical batch numbers were found at separate addresses lived in by a murder suspect and the home of the couple he is accused of killing, a trial has heard.

On the 13th day of the Mersea murder trial, Luke D’Wit faced questions from the prosecution about fentanyl patches which he is accused of using to poison Stephen and Carol Baxter last year.

The couple were found dead inside their conservatory in Victory Road, West Mersea, and a coroner later concluded lethal levels of fentanyl in their blood had contributed to their death.

Mrs Baxter also had a lethal level of promethazine in her blood, a coroner found.

Gazette: Post-mortem - a coroner ruled that both Stephen and Carol Baxter had died of fentanyl toxicityPost-mortem - a coroner ruled that both Stephen and Carol Baxter had died of fentanyl toxicity (Image: Press Association)

At Chelmsford Crown Court on Tuesday, the court heard how the batch numbers of fentanyl patches which were found at the Baxters’ home address matched the batch number of the fentanyl patches which were found in D’Wit’s home when it was searched last July.

The patches which were then found in the Baxters’ house also had D’Wit’s fingerprints on them, the court heard.

D’Wit, 34, claimed the patches – found inside his bag when he was arrested at Essex University campus – had belonged to his late father, Vernon D’Wit.

The court heard how D’Wit had been finding more and more patches in his father’s house after Vernon D’Wit died.

He said: “It took a long, long, long time to go through all my dad’s stuff – he seemed to keep fentanyl patches in various places.

“I kept adding to [the number of patches] as I went on.”

Tracy Ayling KC, prosecuting, said: “The number on those [fentanyl] patches matches the number on the patches found inside 18, Victory Road on July 18.

Gazette: Questioned - Luke D'Wit was questioned by police on the day the Baxters were found deadQuestioned - Luke D'Wit was questioned by police on the day the Baxters were found dead (Image: Essex Police)

“Those patches also have your fingerprints on them.”

D’Wit replied: “I have read some have mine [fingerprints].”

Mrs Ayling KC then asked D’Wit about Phernergan tablets – which are used as anti-histamines – that had been crushed into a powder by D’Wit .

Tablets which contained four times the usual amount of Phenergan were found in D'Wit's bag, and the Phenergan matched the type which had been crushed by D’Wit in his bedroom.

D’Wit claims he had ground up the Phenergan so he could mix the powder with a cream to treat eczema.

The trial continues.