IF KILLER Thomas Griffiths wants to show remorse for the murder of his ex-girlfriend Ellie Gould he must give an account of what happened in the minutes before he stabbed her 13 times in the neck, the detective leading the case said.

When the now 18-year-old Hardenhuish School pupil was interviewed by police investigating Ellie’s death, he initially denied murdering the teen girl. Instead, he claimed he had studied at home that morning before being taken to his school’s nurse by a Derry Hill neighbour concerned that he had been self-harming.

That account fell to pieces as detectives gathered evidence from his phone, from CCTV and forensic evidence from his clothing that conclusively showed he had gone to Ellie’s home that morning.

He has since admitted killing his girlfriend of almost five months – just a day after she texted him saying she no longer wanted to go out with him.

Det Ch Insp Jim Taylor of the major investigations team said: “For him to show a degree of remorse he needs to do more than words. I think he needs to give an account of what happened in the house.

“If he can remember what happened he should bring some closure to the family. For me, that’s what remorse means.”

The senior officer, who leads one of the teams tasked with investigating murders across the region, said the case was chilling.

“There were no precursors to this,” he said.

“There was no information or evidence that we uncovered in our investigation that would suggest something like this was going to happen.

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Police outside Ellie Gould's home on Springfield Drive, Calne

“These were two 17-year-old schoolchildren in the primes of their lives and with the world at their feet.

“For this to happen with no indication is quite chilling.”

He added: “While all murders are tragic, a murder involving two young people like this without any indication – no arguments, no previous assaults, no threats.

“This has gone from nothing to a brutal murder and that is very unusual.”

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Thomas Griffiths Picture: WILTSHIRE POLICE

Mr Taylor said the case had had a profound impact on his officers and staff: “This offence was shocking.”

There will be a domestic homicide review, conducted alongside the council and other agencies to see what lessons can be learned from Ellie’s death.