'Truth or dare' murderer sentenced to life for killing 94-year-old step-grandmother

12 November 2021, 11:00 | Updated: 12 November 2021, 12:37

Tiernan Darnton confessed to the murder of Mary Gregory in a game with two friends
Tiernan Darnton confessed to the murder of Mary Gregory in a game with two friends. Picture: Lancashire Police

By Daisy Stephens

A 21-year-old student who confessed to the murder of his step-grandmother in a game of 'truth or dare' has been sentenced to life in prison.

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Tiernan Darnton was sentenced at Preston Crown Court to life imprisonment with a minimum term of 15 years for the murder of his Mary Gregory, 94, in a house fire in Heysham, Lancashire.

Sentencing Darnton to life, Mrs Justice Yip told him: "Murder had been on your mind for some time. On your own evidence, you were fascinated by serial killers and their crimes. You had dark thoughts.

"Internet searches which you made before and after you killed Mrs Gregory paint a worrying picture.

"Your opportunity to act on your dark thoughts came when your stepfather was away. In the early hours of 28 May 2018, you went to Mrs Gregory's home and deliberately started a fire in one of the bedrooms."

The judge went on: "It is hard to imagine the horror Mrs Gregory must have felt when she realised her house was on fire and was filling with smoke.

"Neighbours heard her screams. Despite her frailty, she tried to get out, but she had been trapped. The fire service found her near to the conservatory doors, where you had blocked her exit.

"Her final days were spent in hospital. Quite understandably, her condition in those days continues to haunt those who loved her. The manner of her death was particularly cruel."

The court heard that "disturbing material" - not presented to the jury in Darnton's trial - had also been found in the defendant's possession including plans to stalk and attack women and a "kill list" containing the names of multiple people.

Read more: Man revealed 'darkest secret' of step-gran murder in game of Truth or Dare

Mrs Gregory was discovered under a table in her conservatory in 2018, after what was initially believed to be an accidental house fire.

She died in hospital four days later and an investigation by Lancashire Fire and Rescue Service ruled out third-party involvement after concluding the fire was likely caused by a discarded cigarette.

However police reopened the investigation after 21-year-old Darnton said in a counselling session that he killed Mrs Gregory, his stepfather's mother.

It then came out that several weeks after the fire Darnton revealed his "darkest secret" during a game of 'truth or dare', telling two friends: "I have a secret I haven't told anyone.

"I may have killed someone."

Darnton said he had started the blaze because he did not want Mrs Gregory to continue suffering from dementia, the court heard.

But Darnton's friends did not believe him and he persuaded them not to tell anyone what he had said.

Darnton made a detailed floorplan of his step-grandmother's house
Darnton made a detailed floorplan of his step-grandmother's house. Picture: Lancashire Police

Then, in 2019, he told a counsellor he had a friend "who could send me to prison 'cause of what he knows".

He also spoke about feeling "powerful" at an event involving the person who had died - thought to be the funeral - because he "knew what happened and everyone else in the room didn't".

After confirming Darnton was indeed telling her he had killed someone, the counsellor passed the matter to the police, the court was told.

Darnton was then arrested in May 2019.

He was convicted by a unanimous jury verdict on Thursday.

It was revealed Darnton had made a floorplan of Mrs Gregory's house that included labels such as 'good hiding place' and 'quick exit'.

It also had references to the doorbell being a 'good distraction', and 'needing a good alibi'.

After Darnton's arrest his laptop was seized and a number of searches were found from the days after the fire, including "feeling guilty for murder" and "mental health support for murderers".

The police investigation also found that the spare key was missing from the outside key box, one of two smoke alarms at the property had been disabled and the home telephone was disconnected, meaning Mrs Gregory could not call for help.