The Melvilles' home community of Methven has also been in mourning following the deaths.

BBC: NEWS | UK | Scotland | Tayside and Central | Man's death increases tragic toll

Both Ms Moore and Mr Methven said there was a lot of ignorance about substance abuse.

BBC: Can a parent save their child from addiction?

After leaving the taxi in North Methven Street, Perth, at about 03:15 on Sunday he attacked the driver.

BBC: Perth taxi passenger attacks driver and two women

He was asked if they had information that Mrs Methven's son may be linked to Strathclyde-based high level criminality.

BBC: Jenny Methven

The jury was read parts of the police interviews which took place in March, the month after Mrs Methven was found dead.

BBC: Jenny Methven

William Kean is still accused of murdering 80-year-old Jenny Methven at her Perthshire home on 20 February this year, which he denies.

BBC: Jenny Methven

But Mr Methven says the reality is that it very rarely works.

BBC: Can a parent save their child from addiction?

Mr Kean denied murdering Mrs Methven but replied "no comment" when asked if he had been in her house and then refused to explain that answer.

BBC: Jenny Methven