Eby was on parole and living about a mile away from the Fox home at the time of Riley's murder. He had no connection to the Fox family, but he has an extensive criminal history, including a separate 2005 charge of criminal sexual assault of a family member, and charges for forgery and a string of burglaries.
For the Foxes, it was shocking to learn that their neighborhood was also home to someone no parent would want near their children.
"I have a new fear that there are people that are capable of doing what he did to her and you don't even know that they're right there. Like that -- that's really scary to me," said Melissa Fox. "She is gone. And there's not this amazing girl here anymore, but there's disgusting people like him here. And that's disappointing."
Prosecutors are assessing whether or not to seek the death penalty.
Authorities initially charged the young girl's father, Kevin Fox, with the murder, based largely on a videotape confession that he'd killed Riley. He spent eight months in prison before he was released and ultimately cleared through DNA evidence.
The family sued the state and won $15 million, which later was reduced to $8.5 million. The state is still appealing the verdict.
After being blamed for her murder, Kevin Fox, the last known adult to see Riley alive, has gone through every parent's worst agony.
"I wish I could have woke up and protected her," he said.
Even though Kevin Fox was exonerated by DNA evidence, there were still people in Wilmington, Ill., who thought Fox was guilty.
"I still had people coming up to me and saying I was a child killer, child molester and threatening to shoot me and my dog," Kevin Fox said. "I honestly found out who my real friends were. I thought I had a whole town behind me and it turned out I have not too many."
Melissa Fox recalled a time when a friend of one of their other children was not allowed to have a sleepover at their home.
"That really hurt, that someone didn't trust us with their child," she said.
The suspicion was one of the reasons why the Foxes moved to another Chicago suburb shortly after the civil settlement and began a new life. In March 2006, they welcomed their third child -- a little girl they named Teagan -- into their family.
But with all they endured, the pain of the ordeal took a heavy toll on the high-school sweethearts' marriage. The couple eventually separated.
"It was difficult," Melissa Fox said. "And then having to go through that trial and to relive everything was very, very stressful and difficult on our marriage and our relationship.
"Although I care about Kevin a ton and I support him always and would defend him always," she said, "it just was too much for our marriage to withhold."
Despite their separation, Melissa and Kevin are unified in their love for Riley.
"I just hope people learn from us, that in life you're given some hard things to deal with, and that's part of life," she said. "You just got to learn live with it. And it makes you stronger, for sure."
CLICK HERE to see photos of Riley Fox and to find out details on the murder case