Tyrell Edwards, 18, was driving a Nissan Navara ute when it crashed into two trees near the Wollondilly Shire village of Buxton on Tuesday night, killing three girls and two boys aged between 14 and 16.
The victims are Picton High School pupils Lily Van De Putte and Gabby McLennan, both 14, Summer Williams and Tyrese Bechard, both 15, and Antonio Desisto, 16.
Edwards was refused bail by a magistrate on Thursday on five charges of dangerous driving occasioning death.
Police prosecutors said a video allegedly taken in the lead-up to the fatal crash supported elements of the offences and showed a high level of moral culpability.
The video, filmed by Edwards on his phone about an hour before the crash, shows him driving with two of the victims, according to a summary of police facts.
Edwards is seen holding his mobile, while aggressively turning the steering wheel, as loud music plays.
A male in the car can be heard saying: "We're going to spin out cuz."
In the moments before the crash, police allege Edwards drove at high speed, lost control, crossed onto the wrong side of the road and travelled along a grassy road shoulder for about 40 metres.
Investigations suggest the ute rotated clockwise for about 50 metres, hit a tree and then rotated in a counterclockwise direction before colliding with a second tree.
The force of the two impacts tore open the ute cabin, ripping the rear seat from the vehicle and throwing the five victims from the vehicle. Their bodies were located nearby.
The court documents state witnesses overheard Edwards say: "I f***ed up, I'm going to jail."
The driver, who suffered minor injuries, will remain in custody in custody until November after his appearance in Picton Local Court via video link on Thursday.
In seeking release, his lawyer argued the 18-year-old was significantly traumatised by the incident.
Edwards graduated year 11 last year at Picton High School - the same school as the alleged victims - and now works as a labourer, the court was told.
He had previously suffered from anxiety and has sought psychological treatment for the illness.
After the crash, Edwards told police the ute span out of control after a steering fault where the wheel was "shaking, going left to right". Braking failed to halt the vehicle, he said.
Picton magistrate Mark Douglass concluded Edwards posed a risk to the community and could tamper with witnesses due to his strong ties to the community.
"It's not an easy decision - he is a young man who has never been in custody," Mr Douglass said.
Edwards had held a licence for a short period of time, had accumulated two speeding offences, and had his licence suspended earlier this year.
The bail hearing needed to be streamed online after a crowd of family members and friends descended on the small, country court.
Exaven Desisto, the father of crash victim Antonio, said outside the court he did not want to see anybody behind bars.
"I've got to visit my son at the f***ing morgue," he said.
Camden police chief Superintendent Paul Fuller, a 38-year police veteran, described the crash site as "one of the worst accident scenes I have ever come across".
Distraught teenagers wearing school uniforms laid flowers and cards on Wednesday at the crash site.
Edwards will appear again in Picton Local Court on November 16.
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