A 16-year-old girl who was gang raped at a party in Sydney’s west may have had her drink spiked before allegedly being assaulted by several males, some of whom are married with children.

Four men aged in their 20s and a teenage boy have been charged with multiple assaults over the incident in St Clair in May.

Footage showing up to eight males in the room with the girl at one time was uncovered after police seized a Go-Pro camera during an operation targeting graffiti offences.

“These are predominantly adult males in their mid-20s and they’re filming a matter like this on a very young … (and) very slight-framed girl,” Detective Chief Inspector Peter Yeomans from the Child Abuse Squad told 2GB Radio on Thursday.

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“These adult males are quite large men – and some of these men are married with children.”

Police believe the girl was either unconscious or semi-conscious at the time and the attack – which she did not report – but officers have since made contact and interviewed her.

“It was quite obvious to investigators when viewing this footage that the child was either unconscious or semi-conscious during these assaults,” Insp Yeomans said.

“There were a number of reasons why she didn’t report the matter – her lack of memory at the time, also her fear of any reprisal.”

The girl is now undergoing counselling.

A 17-year-old boy, a 23-year-old and two 24-year-olds have since been charged with a string of offences including sexual assault in company.

A 25-year-old has been charged with conceal serious indictable offence.

All five have been refused bail and are due to face courts at Penrith and Mt Druitt on Thursday.