Not necessarily so. 'drug paraphernalia' could have just been the syringes and tourniquets used to inject whatever they had on hand.
Fentanyl is used in hospitals, ambulatory surgery centers and doctors offfices. Even with good inventory controls and 'four eyes' rules, you occasionally have diversion of the substance by staff. Fentanyl is short acting and washes out of your system very quickly. You could inject a dose of fenta today and pee a clean urine drug screen tomorrow. The impression that it is 'clean' and doesnt come with the same risks as heroin sometimes causes people who are otherwise not addicts to play around with it. During the time I was a resident, several people at the different hospitals I came through died from fenta overdoses. That was before the current 'heroin epidemic' and none of them were heroin addicts.