Mom opens up about botched police investigation into daughter's murder

Dressed up in a Minnie Mouse costume for her son's school Halloween party, Melissa Fox tried to put on a brave face for her 6-year-old boy and the world.

Just hours earlier, on Oct. 27, 2004, police had made an arrest in the tragic murder of her 3-year-old daughter, Riley Fox, claiming to solve and bring to a close the five-month-long, high-profile investigation.

"On the news, they were telling everybody there was an arrest made. I [knew] who they arrested, but nobody else did yet." Melissa said.

Riley, an adorable, outgoing and bright-eyed toddler, was found murdered in a creek just 4 miles from her home, shaking the small town of Wilmington, Illinois, about 60 miles southwest of Chicago, to its core.

"In an instant, my life was forever changed and it was devastating," Melissa told ABC News.

Watch the full story on "20/20" FRIDAY at 9 p.m. ET on ABC.

As Melissa fulfilled her promise to be with her son at school that evening, the Will County Sheriff's Office was getting ready to announce its suspect: Kevin Fox, Melissa's then-husband and Riley's father.

In an exclusive interview with ABC News' "20/20," Melissa reflected on how she survived a parent's worst nightmare, tirelessly defended her husband's innocence and never gave up fighting for justice for her beloved daughter.

Riley Fox is found murdered

On June 6, 2004, the lives of the Fox family changed forever.

That weekend, Melissa, then 25, and a group of friends participated in the AVON Walk for Breast Cancer in Chicago, where she stayed for two nights -- the longest she'd ever been away from her children. Kevin stayed home with the kids.

Melissa adored Riley and cherished her time with her little girl.

"She had this perfect black hair and perfect little round face and blue eyes," Melissa said. "She was funny. She was silly. Just, so talkative, and she was friendly to everybody she met. She was just a sweetheart."

"Riley was a lot like Melissa," Jillian Garrelts, Melissa's friend, said. "She was a spunky, sassy little girl. She ... could be a little princess... But ... she was a daddy's girl, kind of a little tomboy [who] loved to fish ... and wasn't afraid to get dirty."

While his wife was in Chicago, Kevin, then 27, and the kids spent Saturday afternoon making posters in anticipation of celebrating Melissa's walk at the finish line, where they planned to meet her the next morning.

But early Sunday morning, Tyler woke up Kevin to tell him that Riley was missing.

Not thinking it was a true emergency, Kevin looked through the house and backyard. Then, after about 30 to 40 minutes, Kevin called the non-emergency number for police. He reported finding his front door open and Riley's yellow blanket still on the couch, where she had been sleeping.

Meanwhile, in Chicago, Melissa and her friends were nearing the end of their walk when she called her husband to check in.

"He sounded so startled. I knew immediately something was wrong," Melissa said. "He just said, 'Riley's gone,' and I immediately hit the ground and the phone fell out of my hand."

The women rushed back to Wilmington, where word of Riley's disappearance had spread quickly throughout the small town of 5,000. They arrived to see the community mobilized, with dozens of volunteers searching for Riley in ditches, woods and the town's forest preserves.

"It was something out of a movie... [I] feel like the entire town was out looking for her," Colleen Hansen, Melissa's friend, said. "Every area of the town was being canvassed in some fashion."

For hours after Melissa had arrived, the town continued to search high and low for Riley. Then at one point, Melissa said a police officer placed her and Kevin in separate police cars.

"I didn't understand what was going on. When we got to the police station, they just started asking questions and I was like, 'Is someone going to tell me what's going on?'" she said.

The couple was unaware that two volunteers had found Riley facedown, wearing only a shirt, in a creek. She had duct tape across her mouth and what investigators believed to be duct tape residue on her wrists. Autopsy reports later determined that she had been sexually assaulted and drowned.

"It was just crushing," Melissa said. "I couldn't even stand. I couldn't even think. I couldn't even imagine what life would be like without her."

From that moment forward, Melissa said she never stepped foot in the house where Riley had disappeared from again.

Police focus on Riley Fox's father in her murder

Nearly 6,000 people attended Riley's funeral a few days after she'd been found.

The attendees wore pink, Riley's favorite color, and buttons with her picture on it while Martina McBride's "She's a Butterfly" played through the speakers. Riley was buried in the white flower girl dress she had worn to her uncle's wedding just two weeks before her murder and new flip flops that she'd wanted.

Melissa later learned Will County Sheriff's Office detectives were also in attendance, videotaping Kevin.

"Within an hour of the funeral ending, [the police] came to my house," Hansen said. "They asked if there was any reason that I would believe Kevin to be capable of doing something like this. ... Before the question even came out of their mouth, my answer was, 'No.'"

Desperate to find out what happened to her daughter, Melissa said she reached out to the detectives every day and that they assured her they were investigating the case thoroughly.

Then, nearly three weeks after Riley's murder, the detectives asked to speak to her brother, 6-year-old Tyler. Melissa and Kevin agreed.

For over an hour, a forensic interviewer questioned Tyler about Riley's disappearance. On a videotaped recording, Tyler was seen crouching into his chair, covering his face and crying while the interviewer questioned him.

He told the interviewer 168 times that his father had nothing to do with the disappearance of his little sister, according to Fox's attorney Kathleen Zellner.

When Melissa was able to view the recording at a later date, she was distraught. She said she allowed her son to be questioned because she trusted the detectives.

"It was really sad to watch," Melissa said. "Our family had been through so much. I had just lost a child and then to see the way that they decided to treat the one I still had was really terrible."

Riley Fox's father is arrested for her murder

Months passed with little movement on the case. On Oct. 26, 2004, the Foxes received a call from the Will County Sheriff's Office asking them to come to the office as there were new developments in the case.

"I was like, 'Oh my gosh, this is it. They found the person," Melissa said. "We were just grinning from ear to ear like we're finally going to know what happened."

But immediately upon their arrival, Melissa said they were separated and Kevin was taken to a backroom for questioning.

"Something just [didn't] feel right," she said. "I thought they were going to tell us what was going on. I [didn't] know what's happening."

"I was stunned... For months, [I had been] telling [them], 'Stop looking at my husband. Kevin had nothing to do with it,'" Melissa said.

About eight hours into Kevin's interrogation, Melissa said police told her Kevin had agreed to take a polygraph exam and that he had failed. Melissa said she then spoke to her husband.

"As soon as I got in the room ... I think they were really upset, that they thought they had me believing their story. And the second ... I let Kevin know, 'I don't believe them. It's OK' ... They didn't want me anywhere near him," Melissa said.

She said the sergeant overseeing the investigation pulled her out of the room, yelled obscenities in her face and insisted to her that Kevin had murdered their child. The Will County Sheriff's Office has denied these claims.

At approximately 8 a.m., Will County detectives said Kevin had confessed to killing his daughter. He had been questioned by police for about 14 hours and hadn't slept in more than 24 hours.

According to the detectives, Kevin confessed that he had accidentally killed Riley when he opened the bathroom door and struck her in the head early Sunday morning and that he then staged her death to look like an abduction and murder. Police said that he sexually assaulted Riley as part of the cover-up and dumped her body in the creek.

DNA evidence proves essential in Riley Fox case

When Chad Fox learned of his brother Kevin's interrogation, he rushed to the building where he worked and waited outside the door of a neighboring attorney's office. Chad had suggested months earlier that Melissa and Kevin speak with an attorney, but they felt they didn't need one.

Little did they know, Chad was not referring to just any attorney. He was talking about Kathleen Zellner, one of the best criminal defense attorneys in the country, who has helped exonerate 20 people.

After speaking to her, Chad and Zellner raced down to the sheriff's office. When they arrived, they learned Kevin was already being booked into the Will County Jail.

"I went outside and Melissa Fox was standing in the parking lot... She told me, 'There's just no way that he did this,'" Zellner said. "I thought ... this is a very self-confident, assertive ... person that seemed very intelligent to me, and when she told me that, I thought maybe he didn't do it."

After meeting Melissa and speaking to Kevin, Zellner took on the case.

The Will County State's Attorney filed first-degree murder charges against Kevin Fox and announced they were planning to seek the death penalty against him for the murder of his daughter.

Yet, Kevin denied killing Riley, claiming the detectives threatened and coerced him into giving a false confession. The investigators have denied threatening Kevin and coercing him to confess.

Word spread like wildfire throughout Wilmington and the Chicagoland area that Kevin was responsible for Riley's murder. Chicago media descended upon the small town.

"We went from being the victims of the crime, and having everybody's sympathy to, all of a sudden, we were bad people," Melissa said in a previous interview.

While Melissa's world was falling apart, she said she had to stay strong for her son, Tyler, and her family.

Meanwhile, Zellner sprang into action. She and her team of private investigators traveled to Wilmington and began to reenact the crime to see if it fit Kevin's confession.

She quickly began poking holes in the Will County Sheriff's Office investigation and Kevin's confession. For example, she alleged that the current of the creek wasn't strong enough at the spot where Kevin said he'd placed Riley's body to move her to the location where she was found.

However, in spite of her findings, Zellner felt the only way to overcome Kevin's confession and prove his innocence would be with DNA evidence. In her review of the Will County Sheriff's Office investigation, Zellner found that there was, in fact, DNA from Riley's rape kit that had been available all along, but the DNA required sophisticated technology to further test it.

She was able to strike a deal with the newly elected State's Attorney James Glasgow, who agreed to allow a private lab to test the DNA.

When the results came back, they excluded Kevin Fox, but did not identify the real killer. He was released from jail the next day and the charges against him were dropped.

Kevin spent eight months in jail wrongfully accused of his daughter's murder.

"[Kevin's release] was something I had hoped for and I knew would happen, but some days it just felt like ... forever, and other days, it just felt impossible," Melissa said.

"I [was] really happy to have our family back together, but [we were] still missing a piece," Melissa added. "Still, nothing had helped us understand what had happened to Riley and it felt as if they made it that much more difficult to find the truth because they had so many people believing that it was Kevin."

"[The Sheriff's Office] wasted all that time. ... They really screwed us over big time and I still don't know why," she said.

Fox family files civil rights lawsuit

Upon Kevin's arrest, Zellner filed a civil rights lawsuit against Will County, the Will County Sheriff's Office, multiple sheriff's detectives who investigated the case, the former Will County State's Attorney, the polygraph examiner and the forensic interviewer who spoke with Tyler, and others.

Zellner's claims for Kevin Fox included violations of due process, false arrest, malicious prosecution, intentional infliction of emotional distress, false imprisonment, and conspiracy. For Melissa Fox, claims included conspiracy, loss of consortium, and a claim of intentional infliction of emotional distress against one detective.

"This was not about incompetence. This was a case where we had to show that there was some malicious intent," Zellner said.

Just before the trial, the former state's attorney who filed charges against Kevin negotiated a resolution with the Fox family without admitting wrongdoing.

Zellner said the lawyers for Will County tried to settle with the Foxes, but Melissa and Kevin wouldn't agree to it.

"Why settle? We'd had nothing to hide. ... They raked us through the mud," Melissa said.

Melissa claimed the detectives caused more damage to her family while grieving the loss of her daughter.

"The one person ... who I needed by my side was Kevin, and they took him from me. So, I was mourning the loss of a child," she said. "And ... now I have to raise my son by myself, who's just lost his sister. It was just truly a nightmare, and ... the civil case at that time ... felt like [our] only way to get back at them."

In court, Zellner and her team argued that the detectives had tunnel vision. She said they presented many possible leads that she said they say the Will County Sheriff's Office failed to properly investigate.

Zellner argued that the detectives did not properly investigate a possible break-in at the Foxes' neighbor's home on the night Riley disappeared, and that they didn't follow up on a suspicious red Chevy Beretta that had been seen driving through the neighborhood.

The attorneys for the detectives had said one of the reasons they suspected Kevin was that they found no sign of forced entry into the Fox home and that he didn't immediately call police.

Melissa and Kevin said the lock on their back door had been broken.

The detectives' attorneys argued the detectives had probable cause to arrest Kevin, and that they did not rush to judgment or coerce a confession from him.

All of the detectives involved in this case declined "20/20's" requests to be interviewed.

During the trial, one of the detectives, the polygraph examiner, the forensic interviewer, and others settled out of court without admitting wrongdoing.

The jury ruled in favor of the Fox family on a number of their claims, but not all, finding that the remaining four detectives and the estate of a fifth detective were liable for violating Kevin Fox's right to due process, false arrest and infliction of emotional distress, but not conspiracy or false imprisonment. The jury also held the detectives liable for Melissa's claim of loss of consortium, but not conspiracy. The jury also found in favor of Melissa Fox's claim for Intentional Infliction of Emotional Distress.

Two of the detectives were found liable for malicious prosecution. The jury awarded the family $15.5 million.

An appeals court later vacated Kevin Fox's substantive due process claim and reduced damages for his false arrest claim and Melissa's intentional infliction of emotional distress claim, reducing the payout to about $8 million.

The search for Riley's killer continues

After the civil trial, the Fox family turned its attention to finding Riley's real killer. Melissa called for outside agencies to take up the investigation.

Years passed and Melissa grew weary, but never gave up hope that her daughter's killer would be brought to justice.

In 2009, the FBI took over the case after Will County State's Attorney James Glasgow said it had reached the point where something "drastic" had to happen. Its investigation led them to Scott Eby, a career criminal who eventually confessed to the crime. In his confession, he revealed, among other things, the harrowing details of Riley's final moments.

A year later, Melissa was on her way to an appointment when she received an unexpected call from Zellner, who told her, "We got him." She was referring to the FBI, who had caught Riley's killer.

"I was ... crying and smiling and I just couldn't even believe it," Melissa said. "It was words that I had longed for, but a lot of days felt like I was never going to hear. ... It took my breath away."

Melissa met Kevin at Zellner's office to meet with the FBI agents.

"One second we're sitting there just like, 'Thank you so much for the work you've done,'" Melissa said in a 2010 interview. "And then, the next minute, crying so hard that you couldn't breathe and just being sad for [Riley]."

"Most people say 'a dream come true.' It was like a nightmare come true," she added.

Melissa said Will County officials and the detectives involved in Riley's case never directly apologized for what they'd done to Kevin or what they had put the family through. But following Eby's arrest, a spokesman for the Will County Sheriff's Office issued an apology to the family.

"I can forgive a mistake. You know, people are human. I get that. But ... they almost completely ruined our chances of ever knowing what happened to our daughter, and so, I hate them for that," Melissa said.

Eby pleaded guilty in 2010 and Melissa finally faced her daughter's killer in court. She described him as "pathetic." Speaking directly to Eby in a victim impact statement, Melissa called him a monster, a coward and a "disappointment to his mother, family and society."

"Although you took [Riley] from me, you cannot take the time I shared with her," Melissa said in front of a packed courtroom. "I will always treasure those memories and feel so lucky to have [had] the privilege and honor ... to have been Riley's mom."

"Riley is the one we will all remember," Melissa said. "She's our little princess."

Melissa asked for Eby not to receive the death penalty so that he could spend the rest of his life thinking about what he had done to Riley and their family.

Eby was sentenced to life in prison without parole. For Melissa, justice was bittersweet.

"[There was] definitely some closure, some peace, knowing that ... [Eby] was going to pay the price for what he had done, but ... could it ever measure up? No," she said.

Remembering Riley Fox

In the years that passed after Riley's murder, Melissa and Kevin had another child -- a daughter -- but their marriage couldn't survive the trauma their family had endured.

They moved, got divorced and are both now remarried with new families.

"Melissa's a remarkably courageous, resilient person who had the character to stick with [Kevin] because she knew he was innocent," Zellner said. "She believed in him. It was an extraordinary story of tragedy, but redemption ... and going forward ... resiliency," Zellner said.

Looking back over the past 17 years, Melissa reflected on the lessons she learned fighting for justice for her daughter and trying to protect her family. She thinks Riley would be proud of the way she fought for them.

"I just feel like ... you have to be your own advocate. If something doesn't feel right, just you have to protect yourself," Melissa said. "Trust your gut."

She no longer lives in Wilmington, but often visits a memorial garden that was dedicated to honor Riley as well as her grave. Riley would have been 20 years old this year. Melissa said the world missed out on a "bright light," but that she knows Riley is watching over her.

"I like to think of the day she was given to me, not taken away," Melissa said, reflecting on Riley's birthday.

She added that despite the many struggles and heartache her family has endured, she refuses to be defined by tragedy.

"I fight every day to be happy and to ... live my life to the fullest for Riley and for my other kids. Just like I did when I put the Minnie Mouse costume on [for Tyler]," Melissa said. "I'm gonna keep living... I'm not gonna let [her daughter's killer] destroy any more of me or my life."

Through it all, Melissa said she's learned to look at life through a different lens, but nothing will be able to replace her little girl.

"Some days are sad. I'll miss [Riley] forever," Melissa said. "It's something I can never really truly recover from, but I'm still blessed beyond belief. It will forever be devastating, and I'll forever have a hole in my heart," Melissa said.

"But because I have suffered such great loss," she added, "I see the world and the blessings and love that I have in such a different way."