A corrections officer was dispatched to investigate, but by the time she got there, all she could see was a man running away into the dense forest that surrounds the prison.

It was not until dawn that officers found a package that included a cellphone, tobacco and marijuana tangled in the power lines outside the prison and a small drone that had crashed in the bushes nearby. In the woods, investigators located a makeshift campground, the remote control device used to fly the drone, a bottle of grape-flavored Gatorade and drugs.

"It was a delivery system," said Bryan P. Stirling, the director of the South Carolina Department of Corrections, explaining how the drone's operators had planned to send the contraband into the prison, the Lee Correctional Institution. "They were sending in smaller amounts in repeated trips. They would put it on there, they would deliver it, someone inside would get it somehow, and they would send it back out and send more in."