Danielle Ngametua Kiriau (top) and Shannon James Kiriau died in the crash. Photos / Otago Daily Times / Supplied
The learner driver of an illegally modified Honda has admitted killing two Mosgiel siblings, as further details of the horror crash emerge.
Cameron Charles Presland, 21, of Milton, yesterday pleaded guilty to the manslaughter of Danielle, 17, and Shannon, 22, Kiriau and two further charges of dangerous driving causing injury to his car's other occupants.
Presland had been drinking before he got behind the wheel and was speeding when his unregistered and unwarranted Honda Integra crashed on the Southern Motorway early on May 18 last year.
A police summary of facts said a sample taken at Dunedin Hospital almost three hours after the crash showed Presland's blood contained 79mg of alcohol per 100ml of blood.
The Honda had an after-market turbo, which was not certified, the car was unregistered and had not passed a warrant of fitness test since 2010.
Presland was aware of the vehicle's condition when he took possession, the summary said.
The day before the crash he was seen twice ''rapidly accelerating the vehicle in an exhibition of speed''. On both occasions he was carrying passengers.
Presland and the crash's four victims drove to a party in Chapman St later, arriving about 9.20pm.
The group left the party, where Presland consumed alcohol, about 2.45am.
He crashed the Integra shortly after 3am, soon after entering the Southern Motorway.