It happened around 4 a.m. Saturday in the area of 49th Street and Lancaster Avenue in the Parkside section of Philadelphia.
PHOTOS: Police investigate abduction, sexual assault of woman
Police said the 20-year-old woman was forced at gunpoint into a vehicle. She was bound by duct tape, then physically and sexually assaulted.
The woman was able to free herself around 3 p.m. Saturday at South 57th Street and Larchwood Avenue in West Philadelphia.
Neighbors say they heard a woman screaming, and ran to see what was going on.
"I heard the screaming though," said witness Moe Wright. "I kept hearing her say, 'Get off me. Get off me.' "
Neighbors say they saw a distraught woman flagging down cars to ask for help. Then they saw two men hop in a car and take off.
It's not clear exactly how the woman escaped.
"The people said she got out of the trunk," said Wright.
"Bloody face, just a shirt on, duct tape on her ankles," said witness Tarrell Pollard. "I'm like really?"
Passersby on the corner helped the woman and called 911. A witness tells Action News her teeth had been knocked loose, and the kidnapper had said he would kill her.
"I came outside. She was walking that way. She only had half her clothes on and she was bleeding real bad," said Wright. "And she made it down to this corner on 57th Street, and the guy was like, 'They must have had her tied up.' She was crying and real hysterical."
The shocking ordeal has neighbors holding their loved ones closer.
"It's a good neighborhood, good block. Nothing usually happens out here," said Pollard. "It makes you want to watch out for people that's closer to you, and tell everybody to be safe."
Detectives were on the scene Saturday in West Philadelphia collecting potential evidence, including duct tape.
The suspect is described as a 23-year-old dark-complexioned black male with dreadlocks and a long beard. He was seen driving a black vehicle with four doors and tinted windows, with the rear driver side window covered with a trash bag.
The Special Victims Unit is investigating.