Family of youngest officer killed in Melbourne freeway crash say 'bright light' is lost

Parents of constable Josh Prestney, 28, say they 'cannot fathom the circumstances' that led to their son's death

The family of a police officer killed alongside three colleagues when they were struck by a truck on a Melbourne freeway on Wednesday say they have lost their "bright light".

Constable Josh Prestney, 28, was the youngest of the four officers killed in the incident, which is the single largest loss of police lives in Victoria since 1878, when three officers were killed in a shootout with the Kelly gang.