Investigators in Llano County are working to track down the source of a batch of deadly opioid pills that swept through the county earlier this month, causing one overdose death and the hospitalization of other people.

“It’s going slowly, but we have gotten several tips that have been helpful,” said Chief Deputy Brad Evans with the Llano County Sheriff’s Office, on Tuesday. “No arrests have been made yet.”

No further overdoses or deaths have occurred since the incidents earlier this month, he said.

Investigations into phony opioid pills began after six reported drug overdoses resulted in the death of one person and the hospitalization of others over the past month.

The chief deputy encouraged folks to continue to call in tips.

“If you know something, say something,” Evans said.

Pills found at the locations of overdoses at first appeared to be tablets of pharmaceutical hydrocodone, which is a prescription opioid used to relieve pain, but initial testing showed that the pills actually contained mixtures of codeine and fentanyl, a particularly potent opioid.

A task force comprised of personnel from the sheriff’s office, Llano Police Department, investigators from the District Attorney’s Office and members of the Drug Enforcement Administration’s drug task force are working together on the investigation, according to a news release by Llano County on June 11.

A DEA agent told the News that many such pills originate in illicit laboratories in Mexico and are run by drug cartels but that law enforcement agencies have to work at all levels to combat the epidemic.

“The DEA works closely with all of our partners, at local, county and state levels and other federal agencies, to offer our resources whenever they’re needed,” said Special Agent Sammy A. Parks, public information officer for the Houston Division. “We’re very good at what we do.”

The administration’s seizures of fentanyl in the region that includes Llano County have increased by 600 percent over the past 12 months, he said.