An investigation was launched in St. Mary's County last week after the agency reported suspected tampering with the security seal on a narcotics box at a local medic unit, officials say.
Members of the sheriff's office determined that the seal on a medic box containing vials of fentanyl had been broken.
Further investigation uncovered that the security packaging on fentanyl vials within the medic box had also been compromised.
According to the sheriff's office, "in response to these findings, detectives conducted simultaneous investigations at all county medic units," which led to the discovery of other tampering incidents involving multiple narcotics boxes.
Similar incidents were also reported in nearby counties.
Raley, 39, was ultimately identified as a suspect, investigators say, and he was the lone perpetrator, they added. He was charged with stealing drugs in a previous incident under similar circumstances years ago, according to reports.
He has been serving as the chief since late last year.
No charges have been announced by the sheriff's office.
The investigation is ongoing.
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