Cassidy Traven, from Melbourne in Australia, was 15 when she took her own life after she was bullied relentlessly by a group of girls at her school.
Her distraught mum claims Cassidy was lured to a house party by the bullies and set up to be raped by two teenage boys.
Now a letter Cassidy wrote to her classmates urging them to stop bullying has emerged.
The letter, discovered on her laptop by mum Linda, says: “My name is Cassidy Trevan, and I was raped.
“If anyone every tries this on you trust me it’s worth fighting! Fight! If you don’t you’ll regret it for the rest of your life like I do. You can do it.
“Be careful. Be warned. Be safe.”
Cassidy was just 13 when she was allegedly raped.
She fought with the torment from her alleged attack for two years after until she killed herself.
Her heartbroken mum, Linda, from Melbourne in Australia, has decided to share the letter on Facebook.
She said: “This process of getting Cassidy’s story out there has both destroyed me and given me purpose at the same time.
“I felt so ‘stuck’, I had to get it out there for her, like she wanted but couldn’t manage to do herself.”
She told Nine.com.au: “The bullying started out with just insults and stuff and she got slapped across the face once or twice.”
But she said her daughter’s bullies made their hate campaign worse and attacked her on social media, forcing her to miss a term of school.
When she returned the group of girls apologised and invited her to a festival.
But instead of going to a party the girls asked her to come to an abandoned house where they organised for two boys to rape the young girl, Linda claims.
She adds: “They were older boys that Cass didn’t know. Two girls who sat and waited. Two boys who shared her and timed each other. One boy stood guarding the front door.”
Although the attack was reported to police, Cassidy was too scared to make an official complaint, her mum claims.
Detectives from Victoria Police’s Sexual Offence and Child Abuse Investigation Team met with Cassidy and her mum and number of times before dropping the case due to lack of evidence.
In a Facebook post Linda told her child’s alleged tormentors: “I helplessly watched my precious child wither away before my eyes, mentally & physically, until she rarely got out of bed, until she could no longer take the pain and torment you caused her.”