Detectives in Western Australia's Kimberley are urging witnesses to come forward after a woman was attacked and sexually assaulted just metres from a beach party.
The 31-year-old woman was attacked at a "beach doof" on Cable Beach in Broome in the early hours of Sunday.
Detectives say the woman had walked away from the main crowd at the event to use the toilet when an unidentified man snuck up behind her, struck her on the head several times and sexually assaulted her.
The woman was taken to Broome Hospital with serious head injuries but has since been discharged.
Detective Senior Sergeant Brian Beck said the violent and opportunistic nature of the attack was particularly alarming.
"The act itself was quite horrendous," he said.
He said the man had "taken off into the dunes" after the incident.
The man was described as between 170-177cm in height, with dark skin and a slim build.
Specialist sex assault detectives have flown in from Perth to assist the investigation.
Detective Senior Sergeant Beck said police had received limited information despite about 200 people having attended the party.
"Our investigation is solely focused on the incident that occurred at Cable Beach," he said.
"There were people that have provided information around the victim being at the event, but no one has actually come forward and provided information.
"If they've witnessed the incident itself, that's quite crucial for us and the investigation."
"Doofs" are regularly held in Broome and are known to attract large crowds of locals and visiting backpackers.
"Never really sort of experienced a lot of previous issues with them, but again, when you have a mix of a large number of people, potentially alcohol and drugs, these sort of things can occur," Detective Senior Sergeant Beck said.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000, or report online at crimestopperswa.com.au.
