This possible break in the case comes as family and friends gather to mourn her death.
The mourners were attending her visitation Friday afternoon on the city's far South Side.
The person of interest was reportedly taken into custody Thursday night after he may have told friends that he was in the alley the night that Mya was found. He is between 30-40 years old, and police are not officially saying that they have a suspect in custody. Sources say he is not a relative of the victim and that he may be mentally unstable.
The person of interest works as a scrapper - someone who collects and sells scrap metal. In fact, at least three scrappers were in the neighborhood late Monday night, according to one neighbor.
Anthony Richmond lives right next to the alley, and around 9:30 Monday night, he says he asked three scrappers to pick up an old refrigerator at his home. Richmond says he's told police this story but does not believe those scrappers are the killers.
"They followed me around here, they got the refrigerator. I locked the gate; they pulled off. It couldn't have been later than 10, ten minutes to 10. They were gone," Richmond said.
But the person of interest reportedly has a cut on his right hand, possibly a bite mark. The man is left-handed, which is significant because Mya's injuries were mostly on the right side of her body. Police reportedly expect to execute a search warrant at the man's home soon.
An autopsy determined she died of multiple injuries from an assault. She was beaten and stabbed. No charges have been filed.
The public viewing for Mya was held at a funeral home at Halsted and 101st Friday. And back at her neighborhood, there were some changes underway as well.
Mya may not recognize her old neighborhood now. Since Tuesday night, city crews have been cutting down trees and clearing debris. When she was found in the alley near her home, the area was dense and dark.
"It should have been cleaned up a long time ago. Like I said, we got raccoons, rats, possums running around here, and the city don't do anything. It took a tragedy for the city to decide to do something that should have been done a long time ago," said neighbor Daryl Akins.
On Monday night, the 9-year-old was killed. She had been stabbed. Her father says he found her in the alley near their Auburn-Gresham home when he discovered she wasn't in bed. Police say she was likely lured out of the house by someone she knew.
"It's like a nightmare that is happening, but I know that there is a God. And I know that God is a forgiving God. And I know that whoever did this heinous crime, whether they are tried through the courts or whatever, I believe that God will have the last say in this matter," said grandfather Orlando Barnes.
The start of the viewing was delayed because the funeral home wanted the family to have private time here with Mya before they opened it to the public. The public viewing was scheduled to last until 10 p.m.
The funeral service for Mya is scheduled for Saturday. A visitation begins at 11:30 a.m., and the service begins at 12:30 p.m. at Monument of Faith church.
"I have to say goodbye. They have to say farewell. This is something that no one should ever have to do to their own child. It was hard. It was very hard," said Mya's father, Richard Lyons, in tears after viewing his daughter at the funeral home. "I just talked to her and I told her that that there was already changes made because of her, and that that she didn't go in vain."