Deborah Byrne could not believe what she saw as she scrolled through her Facebook newsfeed.
As messages paying tribute to her 21-year-old daughter Brogan came up again and again, the UK mum started to panic.
One friend had written "Gone too soon", while another said "I can't believe the news."
"I just remember seeing lots of RIP messages," she told The Sun.
"Then a friend of Brogan's wrote to me 'I'm so sorry' in a private message, so I asked what the hell she was talking about.
"She said there had been a horrific crash the night before, on May 22, and she would be there for me.
"That's when I started screaming. The penny had dropped – Brogan was dead.
"At that moment my heart shattered."
After telling her family the devastating news, they frantically tried to find out more about Brogan's death.
"We were desperately trying to get hold of the Northamptonshire Police to get official confirmation of what had happened," she said.
"But because the crash had happened in Oxfordshire, 45 miles away, Brogan's name wasn't coming up on our local police's system.
"I couldn't believe I'd found out about my daughter's death on Facebook."
After a desperate wait, at 1pm on May 23 last year, an officer from Thames Valley Police told them Brogan had died, following a head-on crash the night before.
Also killed in the crash were her three friends Sam Jones, 23, Nicoletta Tocco, 25, and Sam Kay, 26.
The friends had been driving home from a vegan festival in Bristol when they crashed.
Reeling from the news, Deborah said police had visited her home to let her know what had happened, but she hadn't heard them.
"I didn't blame anyone, but it compounded my heartache," she said.
"The police said they'd knocked at my door in the early hours, but couldn't raise me.
"I recall hearing the dog barking, but didn't think anything of it."
Some of the victims' families had been able to be notified by police, which is how news of their death had spread to Facebook.
"I never thought this would happen to our family," she said.
"Brogan was such a lovely, kind girl and now we don't have her anymore and I've been left with so much pain."