The victim is a Chicago Public Schools high school student.
Police say the victim was on her way to school when she was dragged behind a home, hit in the head, and then sexually assaulted. She was found in a backyard about half a block away from Fullerton Avenue, a CPS Safe Passage route for nearby Northwest Middle School.
On Tuesday night, investigators removed from a garbage can containing possible evidence from the crime scene.
Earlier in the day, investigators searched for clues in the snowy back yard of Michael Klockowski, who discovered the girl beaten, bleeding, and half naked. A community alert issued by police Tuesday evening said she had also been sexually assaulted.
"Just opening the door to take maybe a morning sweep of the sidewalks. And to find something like that is just shocking," said Klocklowski.
Klockowski said the girl was bleeding from the head and had a book bag with her. She was conscious, but barely moving.
"By the time I got back upstairs to get a coat and step back outside, the fire department was already here. I could hear her speaking to them very faintly," said Klockowski.
It happened around 6 a.m. Tuesday morning and two bitterly cold hours passed before Klockowski found her. Police sources tell Eyewitness News the victim was walking to get on a bus to a school outside the neighborhood, before any Safe Passage monitors would have been in place.
Still, word of the attack has neighborhood school parents on guard.
"It puts people on pins and needles to where people are afraid now. They don't feel so safe anymore. I'm pretty sure of that," said Demetrius Dawsun, Cragin neighborhood resident.
"It's something to really worry about, you know. I have no words. I feel really bad," said Johana Arana, parent.
"I got to, like, take care of my children, be more cautious, talk to my children and everything," said Juan Gomez, parent.
"One can't help but suspect that somebody might, like this, something so violent that they might do it again sometime soon, so I hope they get him," said Klockowski.
The girl is recovering at Mt. Sinai Hospital. She was taken there Tuesday morning in serious condition. Police sources told Eyewitness News earlier Tuesday night that investigators have not yet been able to speak with her.
No one is in custody.