Methamphetamine was found in the offending vehicle that killed three people in a crash last month.
Police have told Stuff that methamphetamine, consistent with personal use, was found in the ute driven by Haydn David Clark, 20, who crashed killing himself and a married couple near Thames on April 19.
The Drury man crossed the centre line and collided with a car in which Jocelyn Anne Fielder, 64, and her husband Ian, 66, were travelling, near the Kopu Bridge on State Highway 25.
Clark's father Jim, 54, was critically injured but has since been discharged.