Authorities in northern Colorado is warning people about pills laced with fentanyl that have caused at least eight overdoses recently, including at least two deaths.

The pills are shown in the above photo.

The Larimer County Sheriff's Office posted this warning on Facebook:

''The Northern Colorado Drug Task force and Fort Collins Police Criminal Investigation Division is warning the public of pills purchased on the street that may contain Fentanyl. The Fentanyl-laced tablets are believed to have caused eight overdoses, two of which were fatal. The pills were not purchased from a pharmacy.

The Northern Colorado Drug Task Force needs your help. Anyone with knowledge of the source of the pills please call (970)-416-2560. The images attached are of recovered Fentanyl-laced pills."