Tomislav Perinovic returned from the shops to find his son with stab wounds
The three-year-old was in the kitchen of their Tullamarine, Melbourne home
Mr Perinovic called an ambulance for help around lunchtime on January 14
While resuscitation efforts were underway Mr Perinovic went into another room
He then found the bodies of his daughters Claire and Anna and his wife Katie
A coronial inquest will investigate Mrs Perinovic s mental health at the time