The heartbroken mother of a British woman, who was allegedly shot dead by her father during an argument over President Donald Trump, is demanding a new investigation. 

Lucy Harrison, 23, was shot dead in the chest on January 10, 2025, at her father's home in Prosper, Texas. 

Her father, Kris Harrison, 52, claimed the gun accidentally went off when he pulled it out of its container. A grand jury later agreed with him, allowing the father to avoid jail time for manslaughter and criminally negligent homicide charges. 

Now, Lucy's mother and Kris's ex-wife, Jane Coates, is demanding the Collin County District Attorney’s Office reopen the investigation. 

'I simply want the truth about what happened,' she told the New York Post. 'I want the people responsible for investigating her death to sit down with us and listen to what we have been told by independent experts.' 

Lucy's boyfriend, Sam Littler, who traveled to the US with her, testified that the father-daughter duo had gotten into an argument about the impending inauguration of Trump ahead of his second term. 

He said Kris then led Lucy to the bedroom to show her his gun, and moments later, a gunshot was heard, BBC reported. 

'I remember running into the room, and Lucy was lying on the floor near the entrance to the bathroom, and Kris was just screaming, just sort of nonsense,' Littler said. 

Kris had allegedly been drinking the day of the accident.  

A UK-based inquest was held, where it was determined that Lucy had died by gross negligence manslaughter, a UK crime where a person causes the death of another person through breach of duty of care. This is similar to the US charge of involuntary manslaughter.

'To shoot her through the chest whilst she was standing would have required him to have been pointing the gun at his daughter, without checking for bullets, and pulling the trigger,' Jacqueline Devonish, the Senior Coroner for Cheshire, told the inquest. 

Devonish also referred to Kris as a 'functioning alcoholic,' and concluded that he 'unlawfully killed' his daughter. 

Craig Miller, a retired Texas homicide detective, agreed, telling The Post: 'Guns just don’t go off. The only person who could have fired the gun is the dad.' 

He also questioned the location of the gunshot wound on Lucy's body, saying: 'Why didn’t the bullet come in through the side? It entered directly through the center of the chest.' 

He said the location is inconsistent with Kris's story. 

Police bodycam footage also showed Kris denying that he had been drinking. It was later determined he had allegedly drunk a 17-ounce carton of white wine that day. 

'When a person lies and is inconsistent with their testimony, those are important facts for the police to look at and consider,' Miller told the Post. 

Kris previously said through his attorney that he 'fully accepted' the consequences and that he 'will carry' the weight of his daughter's death 'for the rest of my life.' 

The Prosper Police Department said it would not be reopening its investigation. 

'The case was subsequently referred to the Collin County District Attorney’s Office and presented to an independent grand jury, which ultimately declined to move forward with criminal charges,' a spokesperson told the Post. 

However, Coates, who is flying to the US from the UK, is hoping the DA's Office will change its mind. 

'There isn’t a day that goes by when I don’t think about Lucy and everything she should have had in front of her,' she told the outlet. 

'I want people to see her as a person, not just as a case. She was funny, kind, loving and full of life. She had dreams. She had people who loved her deeply. She deserved a future.' 

Radd Seiger, Coates' lawyer, said in a statement that the police and DA's Office has 'continued to refuse to meet' with the mother. 

'Our door remains open to them should they change their minds. That refusal says more about them than it does about Jane,' Seiger said. 

'The authorities say the investigation was thorough and complete. But where is the evidence that the accidental discharge explanation was properly tested?

'Where is the scene reconstruction? Where is the toxicology on Harrison, a self-confessed alcoholic who was drinking from very early in the morning on the day Lucy was killed, with officers reportedly smelling alcohol on his breath? Where is the gunshot residue evidence? Where is the full forensic picture? Where is the ballistics work? 

'Where is the evidence showing that every obvious line of enquiry was pursued? The authorities simply cannot, and so far will not, answer these questions.' 

Seiger said they have come to Dallas to 'seek justice' and to 'see if the authorities here step forward and do the right thing.'

'All eyes are on them, and rightly so. The ball is in their court. We are going to keep asking for the meetings,' he said. 

The Daily Mail has reached out to the DA's Office and Kris for comment.