CHICAGO (CBS) — 15-year-old Kayleigh Green has been missing for eight days from her Portage Park home without a trace.

CBS 2’s Dana Kozlov reports her parents fear she was lured away by someone online, and into the world of sex-trafficking.

“No one good lures a child from the safety of their parent’s home — no one good does that,” Kayleigh’s mother said.

Anna and Dave Green say they’re broken and desperate to find their daughter. They believe the Taft High School sophomore walked out of the back door of their home in the middle of the night on Oct. 3rd and disappeared.

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(Photo Provided to CBS)

“My worst fear is that someone has her — that she’s being held against her will for sex trafficking,” said Dave. “That’s my gut feeling. I pray to God I’m wrong.”

The Chicago Police Special Victims’ Unit has been on the case for eight days, but no one had heard from Kayleigh since her disappearance. The Green’s say she left a note indicating she was heading to New York. However, she left her phone case and charger behind. Kayleigh also dumped her phone nearby, which sent out pings for three days.

“We believe that she trusted someone. That someone recognized Kay for the really vulnerable child that she is and offered her an escape from her demons — from her depression,” the missing teen’s mother said.

Anna says her daughter usually identifies as a male, plays on her school’s rugby team and started an online teen support group. Anna says Kayleigh has never run away before.

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“There is no way Kay would have left this house without fully trusting someone.”

Kayleigh’s parents believe if they found her phone it may provide some clues as to who she might have gone with or where she’s gone.

They will be back with a group looking for the cell phone again on Saturday.

Police have no updates.