Mayfield — who met with prison officials late Monday — said his office would wait to hear from the FBI before proceeding with investigations.

The ACCC is a privately owned prison but has a federal contract to house inmates.

Authorities want to determine if the FBI has jurisdiction to handle the case.

If the FBI leads the investigation, the ACSO will assist, Mayfield said. The sheriff said he expected to know who would handle the investigation within the next two days.

Because he has not begun investigating, Mayfield did not have details about the climate within the prison when the riot started, but did say the disturbance started because of gang tensions within the prison.

“It started as a fight, either internally between one group or between two groups,” Mayfield said. “Once it started, it kind of quickly spread as a mass hysteria that everyone took part in.”

While the prison houses more than 2,000 prisoners, Mayfield said a core group of approximately 300 were behind the riot.

The prison houses low-security prisoners, most of who are illegal immigrants who committed offenses in the United States and will be returned to their country of origin after completing their sentences.

“There was a lot of confusion inside with the inmates,” Mayfield said.

“One prisoner either fell off or was thrown off the roof of one of the housing units,” Mayfield said.

The prison’s video recording system was functioning in the control room Sunday night, the sheriff said, and he was hopeful the assaults would be caught on tape.

A person purporting to be a prisoner inside the prison called a Jackson TV news station and told reporters there that the riot was because of poor treatment and lack of medical care, but Mayfield said that claim was untrue.

“They said it was about medical and food services, but it was not,” Mayfield said. “Once (the riot) started, they had to say something.”

When the fighting erupted, the prisoners quickly equipped themselves with handmade weapons.

“The prisoners were using mop handles, broom handles, anything they could tear apart from the housing units, anything they could pick up,” Mayfield said. “They were using trash can lids for shields.”

Though witnesses gathered in mass across the highway thought they heard multiple rounds of gunshots, what they heard instead, Mayfield said, was pepper balls — often used in crowd control — that are fired from something similar to a paintball gun, and can sometimes sound like gunfire.

The Federal Bureau of Prisons will ultimately want to review the findings of investigations into the riot, spokesperson Chris Burke said.

“They are working hard to cleanup and organize and get back to normal,” Burke said. “We are going to let them do that. We are there in a support role at this point.”

But that role won’t linger on forever, Burke said. Depending on the results of the CCA reports, the bureau may review its federal contract in Adams County.