A wealthy jeweller has told a British court paranoia led him to believe a letter he found could have been a confession that his son killed his New Zealand girlfriend in their house.
Elliot Turner, 20, is accused of murdering aspiring 17-year-old model Emily Longley in his bedroom at the family home in Bournemouth in Dorset. He denies the charge.
The prosecution at Winchester Crown Court allege that the accused "went absolutely nuts" and strangled Ms Longley in a jealous rage on 7 May last year after he feared she was seeing other men, PA reports.
The court was told he had threatened to kill her and had assaulted her when they argued during the short volatile relationship.
Elliot Turner says Ms Longley attacked him and he grabbed her by the throat for five or six seconds to defend himself and had gone to bed and woke up to find her dead.
His parents Leigh and Anita Turner deny perverting the course of justice.
On Monday, Mr Turner told the jury he did not read the letter from his son to his mother and ripped it up.
The 54-year-old said all he saw was "Dear Mom" in his son's handwriting and had paranoid thoughts of what had happened, so he destroyed it.
Mr Turner later said he had learnt a little of what was in the note when he overheard his wife and son talking about a mallet, an argument and being hit.
Mrs Turner, 51, is expected to give evidence on Tuesday.
On Monday, Elliot Turner pleaded guilty to the charge of perverting the course of justice by persuading his mother to change her story after the count was amended to take away reference to him failing to call an ambulance.