A Gilmer County grand jury indicted three former Calhoun High School students Monday on charges of aggravated sexual battery of a fellow student at an after-prom party.

A girl said she was raped by multiple young men, whom she could not identify, early May 11 at a Coosawattee River Resort cabin in Gilmer County, according to a Gilmer County Sheriff’s Office report. The cabin was rented for a party after the prom, which was held the previous night.

Deputies later arrested Fields Chapman, Avery Johnson and Andrew Haynes, all of whom turned themselves in 18 days after the alleged assault, according to Gilmer Sheriff Stacey Nicholson.

Chapman and Haynes were also indicted on sodomy charges, and Chapman has a separate 28-count indictment involving sexual exploitation of a minor, said Glenda Sue Johnson, clerk of the Gilmer County Superior Court.

Haynes and Chapman both had been arrested months before on underage drinking charges, according to incident reports obtained by The Atlanta Journal-Constitution from Calhoun police. All three suspects played sports for Calhoun High School.

Chapman was on probation at the time of the alleged assault, sheriff’s officials told The AJC. Calhoun City School officials banned all three seniors from graduation ceremonies.

Detectives were very careful with the investigation, interviewing more than 50 witnesses, Nicholson said.

“This has been a very emotional case, certainly for the City of Calhoun and Calhoun High School,” Nicholson said at a May news conference.

The girl told deputies that she couldn’t remember who assaulted her and passed out at the cabin around 2 a.m., according to the sheriff’s report.

“Her injuries were substantial,” Nicholson said.

District Attorney Alison Sosebee noted that aggravated sexual battery is punishable with a sentence of up to 25 years.

The sexual exploitation of a minor charges against Chapman involve a separate person, Sosebee said. They involve digital images or videos that Chapman allegedly possessed on his phone of a minor engaged in “sexually explicitly conduct,” Sosebee said.