Drug users who think they've been sold the wrong narcotics have an ally in a Florida sheriff's department.

Bring suspect substances in and the Putnam County Sheriff's Office will be happy to test them for you.

On Tuesday, deputies followed through on the offer by testing drugs a 49-year-old local man doubted was the crystal meth offered by his dealer.

Deputies in the county, located between St. Augustine and Gainesville, said Douglas Peter Kelly called them, saying he suspected someone had sold him something other than the promised crystal meth.

He said he had a "bad reaction" when he smoked the substance and wanted the drugs tested.

"Kelly told detectives in the Drug unit he wanted the substance tested because he wanted to 'press charges' on the person who sold him the wrong narcotic," deputies wrong on the agency's Facebook page.

"In an effort to ensure the quality of the drug the suspect purchased, detectives told Kelly if he came to the sheriff's office they could test the narcotic he purchased."

Kelly allegedly drove to the sheriff's office and handed detectives a clear, crystal-like substance wrapped in aluminum foil. The substance positive for methamphetamine, "the drug Kelly intended to purchase," deputies said.

Kelly was charged with possession of methamphetamine. He is being held on $5,000 bail at the  Putnam County Jail.

The incident prompted the sheriff's office to post a community service notice on its Facebook page:

"PUBLIC NOTICE: If you believe you were sold bad drugs, we are offering a free service to test them for you."