The NYPD, Sheriff’s Office, and Department of Correction conducted an early-morning inspection of vehicles entering Rikers Island yesterday in an effort to stop staff from bringing drugs into the facility to sell to detainees, Correction Commissioner Louis Molina told staff in a video memo.

The operation came as opioid overdoses become more common behind bars; at least four detainees died from overdoses last year.

“The purpose of this inspection was not to invade your privacy, or due to a lack of trust, but it is because we need to do all we can to mitigate drug contraband entering our facilities,” Molina said in the video, which was obtained by Gothamist.

Molina also told staff Wednesday that he wants to prevent drugs from coming into the jails by scanning letters mailed to detainees and delivering those messages electronically, via tablets, because he alleges that paper can be laced with liquid opioids. To do so — and to implement a ban on personal packages — he is seeking a variance from the Board of Correction next month.

In his message, Molina said staff members at the jails were possibly exposed to fentanyl recently after searching a detainee; they had to be hospitalized and treated. Such increasingly common claims about law enforcement exposure to fentanyl have been controversial, with some experts saying officers are more likely to experience anxiety than an overdose when handling the drug.