The young woman was waiting to be transported to the Kavieng Correctional Institution when the alleged incident happened at around 2am.
Her mother said she was kept in a separate room while the male detainees were in the holding cell.
“They planned it,” the victim’s mother told this newsroom.
“She was the only female locked away in what looked like a store room.
“It’s got brick walls around so when she shouted and struggled, no one could hear from the other side.