LAFAYETTE, Ga. — A former Chattanooga doctor charged with trying to sleep with children will not go to prison.

In a deal worked out last month between defense attorneys and prosecutors, Vikul Vinobhai Patel agreed to move back to India. In exchange, Lookout Mountain Judicial Circuit Assistant District Attorney Chris Arnt agreed not to prosecute Patel.

Patel was arrested in September 2012 on two counts of attempted aggravated child molestation, two counts of attempted child molestation and two counts of violating Georgia's computer pornography law. According to a police report, Patel told investigators he drove from Chattanooga to Rossville because he thought he could have sex with an 11-year-old and a 14-year-old.

The lead investigator on Patel's case, FBI Special Agent Ken Hillman, has been under scrutiny since early 2013. A task force member said Hillman had an affair with a woman and let her investigate "To Catch a Predator"-style cases like Patel's even though the woman was not a trained officer.

Prosecutors with the U.S. Department of Justice said two years ago they were investigating Hillman for a potential criminal case.

Arnt said he could not prosecute Patel without putting Hillman on the stand, but the Department of Justice has "refused" to make him available as a witness. The Department of Justice has also not publicly disclosed the status of the Hillman investigation, making it difficult for Arnt to know when — if ever — the FBI agent can testify.

"This was better than the very real possibility that we might never be able to proceed with this case," Arnt said in an email when asked about last month's agreement.

"The prosecutors agreed to a reasonable resolution," said Brian Steel, one of Patel's attorneys.

According to the police report in September 2012, Patel chatted online with Hillman, who posed as a father offering his children for sex. The two men exchanged emails and talked on the phone. After communicating over a four-day period, Patel drove to a designated location in Rossville, where officers arrested him on Sept. 2, 2012.

Patel told investigators he thought he was going to have sex with children that night, according to the police report. The investigation was conducted by the Northwest Georgia Crimes Against Children Task Force, which was led by Hillman but staffed by local police officers.

Members of the task force posted ads on websites like Craigslist, offering sex with children. Like with the Patel case, investigators hoped to lure potential pedophiles by arranging a meeting at a specific location and place, where officers were waiting.

About seven weeks after Patel's arrest, Ringgold police officer Tom Evans stopped Hillman and Angela Russell as they drove away from a Ringgold bar, allegedly drunk. Instead of testing the driver's blood alcohol level, Evans drove them to a condo in East Ridge.

Evans later said Hillman told him he was having an affair with Russell. Meanwhile, Russell said she helped Hillman investigate a couple of his task force cases, though she is not a trained law enforcement officer and is not named in the investigative files.

Russell has not mentioned working on Patel's case, but defense attorneys began questioning the integrity of all of Hillman's cases. In 2014, the FBI suspended Hillman, and prosecutors with the Department of Justice said they were looking into whether the agent broke the law.

The agreement Patel signed says if he returns to the U.S., the district attorney's office can prosecute him.

Patel used to practice at Nephrology Associates, located on North Lyerly Street. Within days of his arrest, the practice's board of directors suspended him. Last year, the Tennessee Board of Medical Examiners revoked his license.

Contact staff writer Tyler Jett at 423-757-6476 or tjett@timesfreepress.com. Follow him on Twitter @LetsJett.