A B.C. teenager charged with posting photos online of the alleged gang rape of a 16-year-old girl at a Pitt Meadows party last year has entered a surprise guilty plea.

The 17-year-old, who cannot be named under the Youth Criminal Justice Act, copped to one count of making and/or distributing obscene material in Port Coquitlam provincial court Monday.

The charge carries a maximum jail term of two years. Crown prosecutors stayed a separate count of possessing child pornography.

The alleged assaults took place on Sept. 10, 2010 at "Another Night in Bangkok," a Friday night rave on a residential acreage, and in front of up to a dozen onlookers, according to police.

At least one witness took pictures that were later posted and widely shared on social media sites such as Facebook, leading investigators to describe the case as "appalling" and "morally disgusting."

One Facebook group was also formed casting doubt on the victim's story and accusing her of "asking for it."

The girl's father, who CTV News has not named to avoid identifying the victim of a sexual assault, made a plea to have the images removed from the websites shortly after the incident was made public.

"The rape continues with all the photos and comments on Facebook," he said. "It makes me sick."

In January, the alleged victim said she was forced to leave school because of bullying.

Two young adults have also been charged. Maple Ridge resident Colton Ashton McMorris, who was 18-years-old at the time of a January 2011 RCMP press release, has been charged with sexual assault in the alleged rape.

Dennis John Allen Warrington of Langley, who was 19-years-old in January, has been charged with possessing child pornography. The men are due to appear in court in 2012.

Mounties have said they do not anticipate any further charges.

A sentencing hearing for the youth who pleaded guilty is expected next month.