COLUMBUS (AP) — An Ohio prosecutor is asking a judge to deny bond for four men accused of possessing a kilogram (2.2 pounds) of fentanyl.

Franklin County Prosecutor Ron O’Brien in central Ohio said that amount of pure fentanyl could potentially kill thousands of people. Columbus police seized the fentanyl, three guns and $10,000 in a Thursday raid.

Fentanyl, a synthetic opioid far more powerful than heroin, has been blamed for thousands of deaths around the country.

The deadly drug is often mixed with heroin or painkillers, sometimes without the users’ knowledge.

Dr. Anahi Ortiz is the coroner for Franklin County, which includes Columbus. She issued a warning earlier this week after five fatal drug overdoses in 12 hours, with injected opioids the suspected cause of those deaths.