VERNON, Ind. (AP): A southeastern Indiana sheriff says a wave of drug overdoses that killed one person and left 14 others hospitalized was caused by heroin that may have been laced with a powerful painkiller.

Jennings County Sheriff Gary Driver says Tuesday’s overdoses sent deputies racing from home to home across the county to administer an anti-overdose drug to victims.

Driver tells The (Columbus) Republic the heroin was apparently laced with fentanyl or another unknown substance. Fentanyl is a synthetic opioid 50 times more potent than heroin that’s responsible for a recent surge in overdose deaths in some parts of the country.

Toxicology tests will be performed on a Jennings County woman who died to determine what substance she consumed.

Seymour police in adjacent Jackson County also responded Tuesday to numerous overdoses.