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A forensic science student obsessed with the US television drama Dexter has admitted murdering a 24-year-old woman after luring her to a plastic-lined “kill room” inside an Airbnb.

Benjamin William Day, 20, changed his plea to guilty on the second day of his trial at Wolverhampton Crown Court.

Prosecutors said he had carefully planned the killing of Maria Saceanu on 20 December, preparing a room with plastic sheeting and items intended to help him murder her and dispose of evidence.

Day, who was 19 when the murder took place, was remanded in custody and is due to be sentenced on 4 December.

The University of Worcester undergraduate, of Yeadon Close in Redditch, Worcestershire, had been expected to argue he acted in self-defence and had set up the room to film a Dexter tribute for TikTok.

But after an hour-long delay to proceedings earlier, Day returned to the dock and appeared to smirk as he entered a guilty plea.

Prosecutor Rachel Brand KC said he had been fascinated by the programme Dexter, which centres on a forensic scientist in a police department who knows how to cover his own tracks as a serial killer.

Day had set up the the rented room in the Tividale area of the West Midlands to emulate the character – lining the walls and floor with plastic sheeting to cover his tracks and amassing a “shopping list” of items, including an apron, a plastic visor and cleaning chemicals.

The first day of the trial heard that after causing 78 knife wounds to sex worker Saceanu, who he contacted through a website using a burner phone, Day abandoned the “gruesome task” of dismemberment because he cut himself.

Prosecutors claim Day left the Airbnb after the killing, walked some distance away, and called 999 at 00:50 on 21 December asking for medical help.

On body cam footage played to jurors on Tuesday, Day could be seen sitting in a police car with his hand wrapped in duct tape.

He said he had been going to drink in Dudley, and came over to look for a “random girl” in a bar when he claimed he had been injured near a bush by an animal that “might have been a fox”.

Questioned as to where he had got duct tape to wrap around his hand, Day told police it was in his car, although he could not remember where it was parked.

A male officer told him that his story did not quite check out to which Day responded “I don’t know if it was a wild dog or a fox.”

Police were alerted to the scene at the Airbnb by the property’s landlord, who had been contacted by another resident who had booked into a different room and had discovered a trail of blood.

In a statement the resident told jurors they had pushed open the door and saw “a lot of blood on the floor” and what appeared to be a doll.

“The doll was lying on the floor on its back,” they added.

When Day was arrested on suspicion of murder at Russells Hall Hospital in the early hours of the morning of 21 December he was wearing a khaki top resembling one worn by Dexter.

Defence barrister Gurdeep Garcha KC said of Day: “He is well aware of the nature and inevitability of the sentence that must follow.

“It seems to us that given his age and the absence of (previous) criminal offending, the court would be assisted by a pre-sentence report.”

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