Two of the three Calhoun High School seniors accused of sexually assaulting a girl at a Gilmer County cabin while under the influence of alcohol had been arrested before on underage drinking charges, Calhoun Police said.

Fields Chapman, Avery Johnson, and Andrew Haynes turned themselves in to the Gilmer County jail Wednesday morning, 18 days after the alleged sexual assault, Gilmer Sheriff Stacey Nicholson said.

Each was charged with aggravated sexual battery and consumption of alcohol by a minor.

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.

Chapman was on probation at the time of the alleged prom-night sexual assault, Gilmer sheriff’s officials told The AJC.

Calhoun City School officials banned all three teens from Friday's graduation.

Gilmer County sheriff’s detectives only felt confident Tuesday that they had enough evidence to file charges, Nicholson told reporters at a press conference Wednesday in Ellijay.

He said investigators had an idea early on who the suspects might be, but held off on filing charges until they had enough information to be certain.

“As late as yesterday, we interviewed an individual and obtained very valuable information,” he said Wednesday afternoon. “In a case, especially involving teenagers or young people, once you make an arrest, the information flow tends to shut down. We wanted to get all we could get before we put people in jail.”

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,” he said.

“We have worked as fast as we could work to bring an end to this case. But we did not work on Calhoun’s time or on the media’s time line.”

According to a Gilmer sheriff’s incident report, the girl told deputies she was raped by multiple guys early May 11 at a Coosawattee River Resort cabin in Gilmer County. The cabin was rented for after the prom, which was held the previous night.

“It sounds like the party was pretty out of control,” Nicholson said.

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

“Her injuries were substantial,” Nicholson said of the 18-year-old woman.

The three teens are being held in the Gilmer jail. Bond is $51,000 for each of them.

According to Calhoun police, Haynes was arrested in February with two under-aged friends after he was tested for alcohol consumption following a Calhoun High basketball game.

Chapman, police reports said, was arrested last month after he was stopped with a pair of under-aged friends for suspicion of marijuana possession and the trio tested positive for alcohol consumption.

— Please return to ajc.com for updates.