NASHVILLE (AP) — Prosecutors sought an indictment of a top Republican in the Tennessee state House on charges of prescription fraud, but a grand jury in his home county declined to allow the case to move forward.

A drug task force agent alleged that Republican Rep. Jeremy Durham of Franklin had altered the dates of two prescriptions in 2013, according to investigative documents obtained by The Associated Press under state open records laws.

Durham, who serves as House majority whip, said in a statement Wednesday that the case was vetted by a grand jury "who quickly agreed that nothing illegal had occurred." Durham said the prescriptions were ultimately filled and that he "never attempted to obtain anything I had not been prescribed by a doctor."

The name of the drug is redacted in the records, but Durham said it was for the lowest-manufactured dose of Adderall. The stimulant is used primarily to treat attention deficit hyperactivity disorder and sleep disorders.

The investigation began in June 2013, when the lawmaker dropped off a prescription at a supermarket pharmacy in Franklin and an attendant noticed the fill date had been altered from 2012 to 2013. Agent Will Whitney of the 21st Judicial District Drug Task Force confirmed with Durham's doctor that he had not approved the changes to the prescriptions.

The agent came to interview Durham when the lawmaker returned to pick up the prescription, taking him to a parking lot and reading him his Miranda rights.

Durham, an attorney, acknowledged being nervous during the interview with the agent. According to the investigative file, Durham "spontaneously" offered an explanation about the discrepancies on the prescription.

"You're talking about them scribbling that on there? They scribbled that on there," Durham said in the recorded conversation. "You're talking about that three and not that two. I didn't write that."

When pressed by the agent about who had changed the prescription, Durham offered several possibilities, including workers who moved his legislative office and secretaries in the doctor's office.

"I'm trying to defeat probable cause," Durham told the agent, whom he recognized as a political supporter who had put up yard signs for the lawmaker.

Durham said several times that he did not remember changing the prescription himself.

"I would not do that. Do I remember doing that? No. So I didn't," he said. "I did not."

Durham also argued that he had supported legislation to combat prescription fraud.

"I'm passing laws to protect people from this (expletive)," Durham said. "We strengthened this (expletive)."

The lawmaker said he also understood the serious nature of prescription fraud.

"I know the consequences of doing that," he said. "I've handled cases like that. The cost-benefit is not proportional."

Months before the task force report was released, Durham had refused to answer questions from The Associated Press about the investigation. On Wednesday, however, he apologized to a reporter for not being more cooperative and acknowledged that he could have been "less condescending."