As the carnival meandered around the eastern suburbs of Nashville, Mitchell wrote a letter to Donald Locke, a three-time sexual offender who remained inside Florida's secure treatment center.

In the letter, Mitchell described his new job and how easy it would be to abduct a child from the carnival. He even outlined a plan to snatch a young girl, according to law enforcement officers, the center's internal investigator and an offender.

The letter arrived at Florida's commitment center around June 17, the day the carnival pulled into Bloomington, Ind., during the city's Annual Fun Frolic carnival. One offender in the facility read Mitchell's letter and brought it to Kenneth Dudding, the center's internal investigator.

Dudding then called FBI Special Agent John Kuchta.

"This becomes a top priority when you have an absconded sex offender, a fugitive, traveling around with a carnival, someone who has committed sexual crimes in the past and had been civilly committed," Kuchta said.

Kuchta went to work on the case and soon discovered the carnival had set up across the street from an Indiana State Police station in Bloomington.

When police searched Mitchell's van, they found the computer disks of child pornography, rolls of duct tape, marbles and a canvas sack.

"I was very concerned for the safety of our citizens to have this guy in our state," said Charles Cohen, an Indiana State Police investigator who handles child abduction cases. In fact, Indiana and federal authorities were so concerned about Mitchell they contacted the Center for Missing and Exploited Children to see if any children had been abducted from cities Mitchell and the carnival had passed through. None had gone missing.

"It doesn't get any worse than Gary Mitchell," said Assistant U.S. Attorney Steven Debrota, a member of a federal task force who has prosecuted more than 125 child pornography cases.

"I would put him in the worst class of offenders I've ever prosecuted. He should never have been let out."