In a press conference Sunday afternoon, Sgt. Melanie Oncescu with the Calgary Police Service said they expect to lay charges of abduction, forcible confinement, sexual assault and assault.
Police say the 17-year-old female victim was approached by two men while waiting for a bus around 11:30 p.m. MT.
They then dragged the girl into an alley and sexually assaulted her.
After that, police say she was walked from the bus stop at Taradale Drive and Tara Cove Road to a neighbouring community, where she was held overnight in a home and repeatedly sexually assaulted.
The victim may have suffered a concussion, they said.
She managed to escape the house around 8 a.m. while police say the men were distracted and then fled to her family, who brought her to police.
On Sunday morning, three men from the house were taken into custody but police say only two are currently being held.
Since no charges have been laid, police are not naming the brothers in custody.
Police are looking for any witnesses who may have seen the girl accompanied by two men.