A last-ditch attempt to seek a retrial by a handyman who murdered a doctor and her 14-year-old daughter has been rejected by a judge.

Shahbaz Khan, 51, had told a jury at Preston Crown that Dr Saman Mir Sacharvi, 49, and Vian Mangrio, 14, were alive and well when he left their home in Burnley, Lancashire, on September 30 last year.

But on the 13th day of his trial – just before the barristers in the case were due to deliver their closing speeches – he changed his pleas to guilty to murder and also admitted a count of arson being reckless as to whether life was endangered.

Last week, the father-of-four applied to vacate those pleas entered on June 30 as he claimed he felt unwell, with his brain “controlled” by an evil spirit called Robert, and another, named Tony, saying “guilty, guilty” to him as he stood in the dock.

Khan’s new legal team argued that he may have been actively psychotic at the time and a partial defence to murder of diminished responsibility was now open to him to face a possible retrial.

But prosecutor David McLachlan QC submitted that it was more lies from the defendant who had had his opportunity and “should not be entitled to have another go because he didn’t like it last time”.

On Monday, trial judge Mr Justice Goss ruled there was no sufficient basis to conclude it was an exceptional case where the interests of justice would be met by permitting the pleas to be withdrawn.

Khan will be sentenced on Tuesday, alongside his wife, Rabia Shahbaz, 45, who was found guilty of doing an act intended to pervert the course of public justice, namely giving a false alibi to her husband.

Khan, a former computer network engineer in his native Pakistan, strangled psychiatrist Dr Sacharvi and attacked her teenage daughter when she returned from school. Both victims appeared to have been drugged with diazepam.

Vian’s severely burned body was found in the lounge of the property in Colne Road, Reedlay, on October 1, and an attempt had also been made to set Dr Sacharvi’s body alight in the upstairs front bedroom.

Khan was arrested after CCTV footage from September 30 showed him visiting the home where he had previously carried out various repairs including a garage conversion.

Police later found jewellery worth tens of thousands of pounds belonging to Dr Sacharvi in a loft at Khan’s home in Ribble Avenue, Burnley.

Jurors saw post-arrest footage which showed Khan “throw himself” across his police station cell and on to his bed as, he later claimed, a supernatural spirit – known as a jinn in the Islamic faith – named Robert held him by his throat and banged his head against the wall. He went on to say that Robert and another jinn, Rita, lived at the home of Dr Sacharvi and spoke to her as well.

In his defence statement, Khan said he was not responsible for the deaths of Dr Sacharvi and Vian, and told the jury that another person, rather than a jinn, must have killed the pair after he left the house.

In his latest application, Khan said the spirit Tony was controlling him and telling him what to say in his defence statement and when he gave evidence. He added that it was “possible” he had killed Dr Sacharvi and Vian but he could not remember.

Since March, Khan has been treated at Ashworth Hospital in Merseyside and has been diagnosed with paranoid schizophrenia but there was no evidence of any mental disorder prior to his behaviour in police custody.

Ruling on the matter, Mr Justice Goss said: “On the evidence adduced at the trial and his conduct during the trial, it is quite apparent that the first defendant (Shahbaz Khan) has known and understood the case against him.

“He was steadfast in his denial of responsibility for the killings until 30 June 2021 when all the evidence, to which he had paid very close attention, had been called and the initiative then came from him to reconsider his position.

“It is not suggested that his legal advisers overlooked some important matter relating to the case or his mental state, or misrepresented his position to him or put him under any pressure. It is clear he was fully advised as to his position prior to his change of pleas and the consequences.

“He had chosen to advance and maintain the defence that he was not responsible for the killings and fires until then. His mental state had not deteriorated at the time he entered his guilty pleas: there were no concerns from those responsible for his mental health as to his fitness to plead.

“As he had done at all stages, he made clear decisions as to his defences to the charges and his guilty pleas were not underpinned by equivocality.”