Two Cherokee County firefighters have been arrested and charged after an investigation into medications being tampered with on a county ambulance, a sheriff's spokesman said Thursday.

Johnathan Wayne Thomas, 34, of Canton, was arrested at his home Wednesday after deputies conducted a search warrant, Cherokee sheriff's Lt. Jay Baker said.

Jarad Jones, 25, also of Canton, turned himself in at the Cherokee Adult Detention Center on Thursday afternoon.

The investigation of Thomas began after fire officials discovered that vials of medicine on an ambulance had been tampered with, Baker said.

Thomas was charged with the sale of hydrocodone, felony possession of marijuana, and several counts of possession of controlled substances, authorities said. The firefighter was suspended without pay and is being held without bond in the Cherokee County Adult Detention Center.

Jones was charged with felony theft by taking, and his bond has been set at $5,700, Baker said.

Jones is accused of stealing the liquid pain killer fentanyl from a Cherokee ambulance in 2011, Baker said. Investigators believe he stole the drug more than once and that it was for his personal use.

"This agency will not tolerate any type of illegal management or mishandling of our controlled substances, nor will we permit the possession and use of illegal drugs by our employees," Cherokee County Fire Chief Tim Prather said in a statement.

Baker said the investigation into the tampered vials is ongoing, and other arrests are possible.