Police say the single-vehicle crash that took the lives of five young people in Sydney's south-west is the worst they have ever seen.
The circumstances surrounding the crash are still under investigation and the driver — the only survivor — is yet to be interviewed.
This is what we know so far.
A Nissan Navara ute ploughed into a tree on East Parade in Buxton, near Picton, just before 8pm yesterday.
East Parade is a rural road and the crash occurred just outside a residential property.
There were six people travelling in the car, including the driver.
All passengers died at the scene.
The victims were two 14-year-old girls, a 15-year-old girl and two boys, aged 15 and 16.
The identity of one victim has been confirmed as year nine student Lily Van de Putte.
Antonio Desisto, Summer Williams, Tyrese Bechard and Gabriella McLennan, who were all aged between 14 and 16, also died in the crash.
Lily's father John Van de Putte told the ABC: "We don’t hold any grudges against the driver because he is going to go through hell".
A number of people heard the crash and rang triple-0 but police say the families of the victims first heard about the incident over social media.
Detective Acting Inspector Jason Hogan said preliminary investigations indicated speed was a possible factor in the crash.
The car split in half on impact and the ABC understands skid marks were at the scene.
The ute was a four-seater carrying six people and police are working to determine if that played a part in the deaths.
"Obviously having six people in a four-seater vehicle is inherently dangerous and should not be done," Detective Acting Inspector Hogan said.
None of the passengers were sitting in the tray of the ute.
Local resident Mary Pace was one of the first people on the scene and said "bodies [were] pretty much everywhere".
"You couldn't tell where the front of the car and the back of the car was. It was completely mangled."
Superintendent Paul Fuller said it was the most "horrific" scene he had witnessed in his 38 years as a police officer.
Ms Pace said a nurse came to the scene after hearing the crash and tried to resuscitate one of the female passengers.
The driver was yelling for help but eventually got himself out of the car, Ms Pace said.
All passengers were students at the local Picton High School and Superintendent Fuller said they were all from the surrounding towns of Tahmoor and Bargo.
"They are only small communities, everyone knows everyone," he said.
The driver, who is on a provisional P2 licence, was a former student of the school.
The 18-year-old male driver was treated for non-life threatening injuries at Liverpool Hospital and has been arrested for the purposes of mandatory drug and alcohol testing.
The driver, named as Tyrell Edwards was the only survivor.
He was released from Liverpool Hospital today, and police arrested him about 1:50pm in Bargo.
He has been taken to Narellan Police Station where he is assisting police with inquiries.
Detective Acting Inspector Hogan said he tested negative to a roadside breath test at the scene last night.
Police are yet to interview him and cannot indicate whether he will be charged.
Community reeling
Some of the first responders likely knew the victims, according to the local mayor.
"[Buxton] is a very small community ... it's very tight-knit out here and everyone kind of knows everyone," Mayor of Wollondilly Shire Matt Gould told the ABC.
"I'm really at a loss of words as to how to express just how devastated our entire community is today."
NSW Ambulance acting inspector Matt Johnston said the nature of the injuries was "confronting" for paramedics who were now "understandably shaken".
He said some of the first people on the scene were Rural Fire Service volunteers who were trained in first aid.
The Department of Education has sent numerous counsellors to Picton High School today for both teachers and students to consult with.
"We will make that support available not just today but ongoing as is needed," deputy secretary Murat Dizdar said.
Mr Dizdar said counselling was also being organised for nearby primary schools where some of the victims may have siblings.
Police are also sending youth engagement officers to the school for support.