Eight State Capitol Police officers were recently trained in using military-issue semi-automatic rifles that the force acquired.
The agency obtained 10 M-16 long guns through a federal surplus program in 2010 in a deal that only cost the state $20 for shipping on each weapon. The civilian AR-15 rifle is more prevalent in private use.
A spokeswoman for the state Department of Public Safety says it is standard practice to certify some officers with weapons such as these. The small State Capitol Police force is responsible for security at the state government complex in downtown Raleigh, as well as on other state-owned property.
As the first responders to any emergency, the spokeswoman said, it is just as warranted to equip those officers with weapons like that as it is any law enforcement agency.
The Department of Public Safety has had a troubled history with some of the weapons its agencies have purchased, including missing and malfunctioning expensive firearms at the Alcohol Law Enforcement division several years ago.