Quinnett was so certain that Blalock was responsible that she offered to drop all charges against him if he would confess to taking Mikelle.
"I can't imagine not ever knowing what happened to your daughter," she said.
"I said, 'If he could bring some comfort or closure to them, I will walk away from this,'" she added. "[Authorities] said, 'We can't do that because ... it's the state versus Dee Blalock.'"
The Biggses had never heard of Blalock, but they soon learned that police had visited him in the early morning after Mikelle disappeared. Police said Blalock's wife provided an alibi for Blalock, claiming he had been in the garage the entire night.
Police also learned Blalock had seen Mikelle before. He told detectives he had seen her going to her piano teacher near his house.
The Biggses decided the only way to find more answers was to deal with Blalock directly.
After Blalock was sentenced for his attack on Quinnett, the Biggses sent him a letter in prison, asking him directly if he had taken their daughter.
"I told him, 'If I'm wrong ... I won't be able to do enough to apologize to you,'" said Darien Biggs, "because that's a terrible thing to be accused of. ... But I don't care ... if I have to accuse a million different people until I find the right one."
Blalock answered in writing that "I need to make things right with you and your family."
He agreed to meet with the grieving parents.
"I was nervous," remembered Tracy Biggs. "I was kind of shaky."
Darien Biggs described the visit as one with an enormous mission.
"Tracy wanted to look in his eyes," he said. "She just wanted to look in his eyes and know whether or not he was guilty."
The Biggses spoke to Blalock in the prison for an hour and a half.
"He just denied, denied, denied, denied," said Darien Biggs. "He got mad a couple times ... but he never walked away."
The Biggses said they reached a consensus about him immediately.
"As we were walking away, I remember telling Darien, 'I think he did it,'" recalled Tracy Biggs. "His movements ... his jitteriness ... he couldn't look you straight in the eye -- just things ... that would indicate that he was lying."
For Darien Biggs, the full impact of the encounter did not hit home until the next day.
"I was sitting three feet from this guy," he said. "You know, the only thing protecting him was that, you know, glass between us."
Although the Biggses said they believe Blalock was responsible for their daughter's disappearance, they do have doubts -- "just enough to keep me from going down there and getting myself thrown in jail," Darien said.
Mesa police detectives Gissel and Domenick Kaufman said they are investigating Blalock and described him as a promising lead in the case.But they emphasized that the case is still open and that Blalock has not been named as an official suspect.
Blalock repeatedly has denied involvement in Mikelle's disappearance.
In the meantime, Mesa police have interviewed thousands of people and gathered more than 800 items of evidence. The most significant piece of evidence is the pink and purple bicycle Mikelle was riding when she went missing.
Kaufman believes the bicycle is the key to the investigation.