DETROIT —  A federal prosecutor from Florida who authorities say flew to Michigan for an expected sexual encounter with a 5-year-old girl tried to hang himself in his jail cell Thursday but was stopped from harming himself, a sheriff said.

It happened only 36 hours after a U.S. magistrate lifted a suicide watch for John D.R. Atchison, which was put in effect out of concern he might harm himself. Atchison assured U.S. Magistrate Virginia M. Morgan at a hearing Tuesday afternoon that he would not do so.

Atchison, 53, used a sheet in an attempted hanging about 4 a.m., Sanilac County Sheriff Virgil Strickler said.

Another inmate yelled out to jailers, who kept Atchison from hurting himself, Strickler said.

The 119-bed Sanilac County Jail is in Sandusky, about 75 miles north of Detroit, and U.S. marshals sometimes use it to house federal prisoners. Marshals moved him after the suicide attempt, the sheriff said.

"We called the marshals office and told them what had happened, and they said, `OK, we'll come and get him,"' Strickler said. Atchison's destination was not known.

Atchison, of Gulf Breeze, Fla., is an assistant U.S. attorney in northern Florida, based in Pensacola. He also is president of a youth sports association in his hometown.

He was arrested Sunday at Detroit Metropolitan Airport after arriving for a meeting with what he thought was the mother of a 5-year-old girl with whom he arranged to have sex, authorities said. In fact, the woman was a Macomb County sheriff's detective and part of an Internet sex sting operation.

Messages seeking comment were left by The Associated Press on Thursday for defense lawyer James C. Thomas, who argued Tuesday for lifting the suicide watch order for his client.

Thomas told The Detroit News that he felt "as bad about it as anyone."

"We all operate on the best of intentions," Thomas said. "At the time, I thought it was the right decision. Apparently, it was a mistake."

Atchison is charged with three felonies, the most serious of which is crossing state lines with intent to have sex with someone under 12. Conviction carries a minimum 30-year prison sentence and a maximum of life.

Atchison, a married father of three, is president of the Gulf Breeze Sports Association. The group runs youth baseball, softball, cheer leading, soccer, football and basketball programs. It said that it placed him on leave until the charges are resolved.