Rottnest Island assault: Police arrest young boy after teenage girl allegedly sexually assaulted in toilet

UPDATE: A 14-year-old boy who was arrested in connection to the alleged sexual assault of a teenage girl in a toilet block on Rottnest Island at the weekend has now been released from custody.

Rottnest Island was at the centre of a wide-scale police investigation on Sunday amid allegations a teenage girl was sexually assaulted in a toilet block.

Amid an influx of teenagers visiting the island during the first weekend of school holidays, specialised forensic officers, including staff from the sex crime squad, travelled from the mainland on Sunday afternoon to begin inquiries.

Police have confirmed the victim is a 15-year-old girl and that she was allegedly sexually assaulted by someone known to her.

The incident happened between 8.30pm and 11pm on Saturday, according to investigators.

Another teenager is assisting police with their inquiries.

One person on the island said while Rottnest was relatively quiet for the summer school holidays, there were lots of younger teens currently on the island, and rangers had provided increased security presence.

An image provided to The West Australian showed a large number of officers standing outside a taped-off toilet block near the Rottnest Hotel on Sunday afternoon.

The toilet block on Bedford Avenue is adjacent to the Hotel Rottnest, near the main ferry jetty.

A WA Police spokesman confirmed investigations were in their early stage, with officers leaving the island late on Sunday afternoon.

Anyone with information relating to this incident is asked to call Crime Stoppers on 1800 333 000 or report it online at crimestopperswa.com.au.