Witnesses found a young woman bound, bloody and yelling out for help Sunday night after a violent sexual assault at a Surrey apartment.

The 21-year-old victim was discovered by building manager Adel Masoud, who came to investigate after a neighbour reported screams coming from one of the units around 7:30 p.m.

Masoud told CTV News he heard a woman crying, then saw her run into the hallway. She was bleeding from the neck, naked from the waist down, and had her hands tied in front of her with what appeared to be skipping rope.

“She came down and she’s shouting, ‘911, he wants to kill me! 911, he wants to kill me!’ and she fell down in front of the door,” he said.

Masoud’s son and a tenant called police to the building, located on 108 Avenue in the Whalley neighbourhood, and helped the woman while Masoud guarded the door.

Mounties and paramedics arrived and the victim was taken to hospital with significant but non-life threatening injuries, including what are believed to be stab wounds.

“I thank God because we arrived at the right time,” Masoud said.

Officers also later took a 22-year-old man into custody.

Court records reveal Kris Kelly is facing several charges, including aggravated sexual assault and attempted murder.

Cpl. Scotty Schumann said investigators are still working to determine the circumstances that led up to the crime.

“We do know that the victim and the suspect are acquaintances, so they’re known to each other, but we’re not sure exactly what precipitated this event,” Schumann said.

There is no risk to the general public, according to the RCMP.

Forensics and serious crime investigators remained at the apartment throughout the day collecting evidence.

“[The victim] did leave a trail of blood that led from a residence to outside, and that’s a very large area that needs to be examined closely,” Schumann said.

Anyone with information on the attack is asked to call the Surrey RCMP detachment at 604-599-0502, or Crime Stoppers at 1-800-222-TIPS to remain anonymous.

With a report from CTV Vancouver’s Michele Brunoro