"I saw a lot of positive things coming from him," Clyburn recalled. "He was dressing the role, he was playing the role, and people were responding to him."
But Juan kept getting sidetracked. He got into fights and was suspended from school. Bill's wife, Brenda, sometimes wondered whether they had taken on too much. And then Juan Carlos Castro made one of the biggest mistakes of his life.
Just five days away from the end of his probation, he took the Clyburns' car out for a midnight visit with his girlfriend. He had planned to be back before anyone woke up. But he wasn't.
Said Juan: "I got tired of being...what they want me to be and pleasing everybody else. And then I can't even breathe 'cause I got to be somebody else that I'm not."
The Clyburns were enraged. "This is not his second chance," said Bill Clyburn. "This is probably his infinite chance in this house."
Sociologist Bill Clyburn thought a stable, comfortable home could save Juan. He was wrong.
To teach him a lesson, Bill Clyburn decided to have Juan arrested for stealing the car. Juan pled guilty and was put on probation. But then Juan violated his probation, by leaving the state and going back to his hometown of Newark to look for his family. There he got arrested for stealing a purse.
He was extradited to Florida, where he was picked up by Detective Semellan.
"Basically it's almost like I went through a relapse," Juan said from his jail cell. "I just left. I just threw my hands up and I really didn't care about much."
Juan had blown his last chance to avoid adult prison. He was sentenced to 16 months there. Detective Semellan felt that he had failed his young friend.
One year and four months later, Juan was released.
Had prison helped him?
He thought so: "I learned who I really am, what I really should do. I always thought that I can't do nothing else but steal cars. I can do a lot more than just steal cars."
Juan was now classified as a repeat offender. If he committed another crime within three years, he automatically would get the maximum sentence.
But once again, Juan seemed to be getting his life together. With the help of Detective Semellan, he got a job in est Virginia working with students.
Juan was a natural: "He's friendly, he's charming, he's interesting," said his boss there, Kim Roselle. "He very much wants to make a difference. He had a wonderful rapport with the students."
Semellan was hopeful: "I thought maybe, just maybe, we've turned the corner. Maybe my boy has become a man."
Detective Carlos Semellan had high hopes for Juan.
"I'm not gonna justify it," he said, in jail once again. "I did it and gotta face the consequences."
In addition to the robbery charges he faced for purse snatching, he was also charged with two burglaries. Because of a new Florida law intended to crack down on repeat offenders, Juan suddenly faced a life sentence without parole - a harsher sentence than most murderers serve.
"I'm fighting for my life," he said.
The prospect of a life sentence shocked Semellan. "He's a human being," the detective said. "This is a real live kid. This is not a monster."
But others believed that Juan was getting his just desserts. "Juan Carlos Castro is a criminal," said Tampa District Attorney Jim Rawes, who had prosecuted Juan Carlos Castro three times.
"Juan Castro made choices and he made decisions. He acted on those choices and decisions and continued to commit crimes," Rawes declared.
The jurors in the purse-snatching case agreed with Rawes. After 15 minutes of deliberation, they convicted Juan of robbery. Juan was also facing more serious charges, for armed burglary.
He said he was just acting as a lookout: "I didn't just go into somebody's house with a damn gun. That's not what happened."
The key, though, was Juan's criminal history. If convicted on these charges, he would have received life without parole. If he pled guilty, he could get 35 years. There would be no hope for appeal and no chance for parole; but he would have the prospect of being free.
Juan took the plea bargain. "Thirty-five straight years," he said miserably. "I'll never see the street again."
At his sentencing, at age 19, the only people who showed up to offer support were Bill Clyburn and Carlos Semellan. Both men, who had fought to save Juan, came to see him through his most difficult moment.
As Juan was sentenced, Detective Semella became too upset and had to leave the courtroom. "I'm sitting there thinking, 'My God, what are these people doing? We have people out here in our society who've done more grievous things who'll still walk the streets,'" Clyburn said afterward.
Even the judge, Peter Dubensky, would have imposed a lighter sentence, if he could have. "I've seen people who commit homicides who get less severe punishment," he said.
But the new law gives no leeway. Given a choice, he probably would have sentenced Juan to a six- to eight-year term, Dubensky said.
"I messed up again," Juan said. "But I don't think I should spend the rest of my life in prison. What does it prove?"
But Rawes said that Juan has had more than enough chances.
After the sentencing, Lee Vallier, the boot camp commander who at one time had been close to Juan, said that he always knew he would fail.
"When families would come to see other people, he had nobody," Vallier remembered.
"Nobody would come to see him," he said. "And I thought 'How is this kid ever going to make it in life?' I mean, who's going to love this kid? Nobody ever really did. And I knew that he would turn around and not love anybody. I knew that."
For his part, Semellan said he will never give up on Juan, even now.
Juan was angry, mostly at himself. "There's nobody to blame but myself," he said, choking back tears.
In the end, Juan blamed himself for his mistakes.
Juan felt especially bad because he knows his daughter is going to grow up the same way he did - without a mother or a father. Juan said he would like to apologize to his daughter, for failing her.
And Juan was not the only one who felt like a failure: "When this kid was found at 6 years in a car by himself, we didn't do what we needed to do," Semellan said. "Bottom line. We have failed."
Said Vallier: "I think the beginning of the story told the end of the story."
To review Juan's story read "Smart, Charming, Incorrigible?"
Produced by David Kohn;