UK has 'no authority' over death of woman shot in US

The grand jury had decided there was insufficient evidence to bring criminal charges after Kris Harrison said the Glock handgun discharged accidentally while he was showing it to his daughter.

In February, a coroner in England concluded Lucy had been unlawfully killed, finding that her father's actions amounted to gross negligence manslaughter under UK law.

Police in Texas have, however, said they would not reopen the investigation.

Evans said the force was "ultimately constrained by legal, jurisdictional and practical realities that significantly limit what any police force in England and Wales can do in relation to a death that occurred in the United States," he said.

Given the "unusual circumstances reported" of Lucy's death, a Senior Investigating Officer had been tasked with looking into the case.

That officer appointed a Family Liaison Officer and sought information from the relevant United States law enforcement agencies.

He said that despite the "clear jurisdictional limitations," the force's actions "reflected our recognition of the exceptional circumstances of the case and our commitment to providing whatever support and assistance was realistically available."

The family had argued that as Kris Harrison is a British citizen, a mechanism exists under certain circumstances, where those from the United Kingdom who commit murder or manslaughter, can be prosecuted before British courts.

In response, Evans said: "Even where jurisdiction may arguably exist in law, the practical ability to investigate and prosecute remains severely constrained when the suspect, witnesses, exhibits and evidential opportunities are all located overseas.

"No parent should have to endure the loss of a child in such tragic circumstances, and I fully appreciate that the passage of time does not diminish the family's need for answers or their determination to understand exactly what happened to Lucy," Evans added.

Coates' lawyer Radd Seiger, has since said the family had "serious concerns about the investigation and whether all the relevant evidence was properly gathered and considered.

Further information, including a recent download from Lucy's mobile phone, contained information which "we believe are relevant to the circumstances leading up to her death."

"We are not asking Cheshire Constabulary to take over an American investigation or to determine what happened in Texas.

Instead, he said they were asking the force "to obtain and examine relevant evidence which has not yet been properly investigated".

"The family have spent nearly two years trying to get answers about Lucy's death and justice for her.

"They are not prepared to accept that the investigation is complete simply because the American authorities have decided not to take the matter further," he added.