Ross Konidaris, the drug addict who admitted to killing his grandparents in 2012, has been sentenced to spend 25 years in psychiatric care.

Konidaris, who shot his grandparents Triantafillio and Stavroula, aged 81 and 84, at point blank range on a Christmas rampage, was found not guilty because of mental impairment and sentenced to spend the next 25 years at Thomas Embling psychiatric hospital. The order, which was handed down in the Supreme Court on Tuesday, can be reviewed as early as 2019.

Yet his family were angered by the decision, saying that Konidaris conned medical professionals and experts into believing he was mentally impaired.

One family told the Herald Sun “he knew exactly what he was doing, he was not crazy”.

The 25-year-old was high on drugs when he broke into his grandparents house on December 22, 2012. He had used cocaine on the night of the double murders, and had already had a long history with drug abuse, namely cannibis, cocaine and ice. He shot his grandfather first, whilst he lay in bed, and shot his grandmother several times before pouring petrol to the house and setting it alight.