Leigh Turner and his wife Anita from Bournemouth in Dorset have been accused of perverting the course of justice, which they deny.

Their son Elliot Turner denies murdering Longley, 17, an aspiring model who was born in Britain but whose parents moved to Auckland when she was aged 9.

The couple had a brief, stormy and sometimes violent relationship. On May 7 last year it is alleged that Turner strangled the teenager following an argument in which he accused Longley of seeing other men.

Father Leigh Turner, who said there was no excuse for destroying the letter, but insists it wasn’t a deliberate attempt at perverting the course of justice, said “I just thought the worst…I didn’t know what it was. It might have said Elliot might have had some involvement, or something written down that might have happened that night. I cannot think what I thought – it was an entity, a void. I felt numb.”

It has been revealed that computers were seized from the family home – with checks on the search history has found that someone had used Google to search for ‘how to get out of being charged for murder’ and ‘death by strangulation’.

The case continues at Winchester Crown Court.