More than $2,800 of a prescription drug used to get high was intercepted in mail meant for the Colorado State Penitentiary, according to a news release from the Colorado Department of Corrections.

The envelope in question was intercepted on Feb. 2 and contained 70 pieces of Suboxone.

According to the DOC, staff can’t read privileged mail but can inspect the contents for contraband while the offender is also present.

Suboxone is typically prescribed to people battling opioid addiction, but is also commonly sold on the street and abused, according to AmericanAddictionCenters.org.

The DOC did not say if the prison who received the drugs will face additional charges.