SAN DIEGO (KABC) -- A counterfeit drug is believed to be the cause of four deaths in roughly a 24-hour span this week in the San Diego area, the county sheriff's department says.
Officials are looking into M-30 pills, which appear to be oxycodone and can be ingested orally, crushed or smoked, authorities say.
The pills actually contain fentanyl, which can be deadly even in a small dose.
San Diego County Sheriff's detectives are working with first responders to determine if other similar overdoses have been reported recently, the department said in a press release.
Authorities have not released any information on the victims or how they obtained the counterfeit drugs.
Anyone with information regarding the drug operation is asked to call the sheriff's department at 858-565-5200.