PITT MEADOWS, B.C. — One man has been charged with sexual assault and another with making and distributing child pornography in the rape of a teenage girl who was drugged and repeatedly sexually assaulted as others snapped photos that were later posted to Facebook.

The attack happened last September at a rave in Pitt Meadows, east of Vancouver, where the RCMP said a 16-year-old girl was drugged and gang raped.

A 16-year-old has already been charged with production and distribution of child pornography related to the incident, and Crown spokesman Neil MacKenzie confirmed charges were sworn Wednesday against two additional men.

Colton Ashton McMorris was charged with sexual assault and Dennis John Allen Warrington was charged with making and distributing child pornography, MacKenzie said.

Both are scheduled to appear in court next Monday, and neither are in custody, he said.

A 16-year-old has already been charged with production and distribution of child pornography.

Sgt. Peter Thiessen of the RCMP said police will release more information at a news conference scheduled for Thursday.

The rape happened on a rural property in Pitt Meadows.

The girl was given the date-rape drug and was conscious during the attack, but she was in a disassociated state and couldn't consent, police have said.

The Mounties have said as many as 12 people saw the attack, but investigators complained of a code of silence among witnesses that was preventing them from coming forward.

The RCMP spent weeks after the rape pleading with Facebook users to stop sharing the photos, warning that anyone possessing or sharing the pictures could face child pornography charges.

Assemblies were also held at local schools to explain the dangers of date-rape drugs and stress the need to stop distributing the photos.

The case followed others in Canadian schools involving teens and inappropriate -- and potentially illegal -- sexual activity.

Earlier that month, police in Calgary laid charges after a 16-year-old boy and a 12-year-old girl who met on a social networking website met in a school field and performed a drunken sex act in front of friends.

Neighbours initially reported that a young girl had been brutally attacked by an older boy in front of a group of young people who were filming the encounter, but those reports proved incorrect. Still, police said they still laid charges because a 12-year-old can't legally consent to have sex with a 16-year-old.

In May of last year, the RCMP in Surrey, B.C., raised concerns about boys in Grades 11 and 12 challenging each other over Facebook to have sex with the most Grade 8 students.

The Mounties sent an officer to the school to explain the laws regarding the age of consent.