Assistant Commissioner Brian Codd said autopsy results would be returned to police on Thursday, with drug and alcohol testing of the 17-year-old charged over the incident also under way.
He was allegedly driving the stolen Toyota LandCruiser that ran a red light, hit a truck, rolled and hit the couple as it did so. He is also accused of fleeing the scene and then trying to steal another car.
Among the mourners at Wednesday nightâs vigil was Ms Leadbetterâs aunty Danielle as well as representatives of the police service, Redlands City Council and local residents, some of whom tried to help the victims.
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Danielle Leadbetter was first told her niece had been killed when a friend sent her a text message and she then saw Katherineâs pictures on news articles.
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