But there's renewed hope of finding the man behind the May 2022 attack near Broome after a $250,000 reward for information was announced on Friday.
It's among the largest rewards offered in Australia for a non-homicide crime.
"This was a random and vicious attack on a young woman, and she continues to live with the aftermath of the incident every day," WA Police special crime detective Luke Fowler said.
"Someone in the community knows something."
The victim, aged 31, was attending the bush-doof event at Broome's Cable Beach in the early hours of May 29.
About 4.30am, she left the main crowd of about 200 people and ventured into the nearby sand dunes to go to the toilet.
There, mere metres from other attendees, an unknown man approached her, struck her to the head multiple times and sexually assaulted her.
She suffered serious facial injuries, police said.
Police have previously described the assault as "quite horrendous" and happening "within sight" of other ravers.
"This amount of money has the potential to change someone's life, and at the same time, help police and the victim get some much-needed answers," Detective Senior Sergeant Fowler said.
The man is described as dark-skinned, slim and between 170cm and 177cm tall.
The reward is offered for information leading to the arrest and conviction of the person or people responsible.
14°C