Police in Baltimore are investigating a sign posted inside a police transport van that tells passengers: "Enjoy your ride, cuz we sure will!"

WBAL-TV reports that a woman sent the station photos she snapped Tuesday when van doors were left open near the central district station.

Baltimore police released a statement Friday calling the sign "concerning and unacceptable." The department says Deputy Police Commissioner Dean Palmere has ordered an inspection of all department vehicles and internal investigations will be initiated "when appropriate."

The revelation comes after six officers were charged in the death of Freddie Gray, who was fatally injured in police custody. An autopsy report leaked to the Baltimore Sun shows Gray died of a high-impact injury as a result of not being secured in a transport van.