The network moved fentanyl and cocaine from Mexico into South Carolina and distributed the drugs statewide, according to investigators. U.S. Attorney for the District of South Carolina Bryan Stirling said incarcerated ringleaders maintained constant contact with suppliers and distributors outside prison walls.

"These people are arrested, sent to prison, and continue behind bars," Stirling said during the announcement. "They used contraband cell phones to arrange deals with distributors on the outside. They would coordinate shipment and delivery of these drugs to organizers in Mexico."

The investigation involved law enforcement agencies from multiple South Carolina counties working together to dismantle the international operation.

The case highlights a persistent problem in correctional facilities nationwide. The Federal Communications Commission estimates that authorities seize as many as 25,000 illegal cellphones inside jails every year, and nearly 500,000 inmates have access to wireless devices that can be used to orchestrate drug trafficking and violent crimes.

Local prosecutors said contraband phones have threatened community safety for years. 16th Judicial Circuit Solicitor Kevin Brackett pointed to a previous murder-for-hire plot in Fort Mill as an example of the danger. In that case, police reported that Jerry Kinard forced his way into a local home, assaulted a woman and attempted to kill her under orders issued by a prisoner using a smuggled phone.

Brackett described how the victim narrowly escaped.

"And only because she had a tremendous amount of presence of mind and courage was she able to conjure up a reason to go back down the stairs and then flee out the door and make good her escape," Brackett said. "Otherwise she'd be dead, and all of that happened and would not have happened if this man in prison had not had access to a cell phone."

For years, state corrections leaders have petitioned federal regulators to permit cell-jamming technology to block signals inside facility perimeters. FCC regulations previously prohibited state prisons from deploying jamming equipment. Brackett said stopping wireless transmissions remains the most effective strategy for protecting prison staff and the public.

"This shuts the cell phones down at the source by preventing the signal from leaving the prison. That's the best solution, and I think that will yield a much safer South Carolina and a safer prison for the people who work there," Brackett said.

The FCC is scheduled to vote next Thursday on whether to allow prisons to deploy cellphone jamming technology. Stirling expressed optimism about the outcome.

The newly announced charges follow other recent law enforcement actions targeting major drug rings in the state. Last month, prosecutors indicted 25 people in "Operation Duffle Bag Boyz," an investigation centered in Lancaster and Chester counties that uncovered trafficking of fentanyl, cocaine, methamphetamine and illegal dogfighting.

Contraband delivery methods have also evolved beyond traditional smuggling routes. In February, officials at a Columbia correctional facility monitored attempts by individuals using airborne drones to drop cellphones and illicit items over facility walls. Prisons have installed dedicated sensors to alert staff to unauthorized drones entering protected airspace so officers can intercept incoming packages.