The military alliance’s procurement agency is under scrutiny for deals on arms and munitions. In a sector with notoriously patchy oversight, defense boom corruption risks are very real.

Revelations of an unfolding corruption investigation involving staff and ex-staff at the NATO Support and Procurement Agency (NSPA) have continued to emerge, with a total of five detentions — two in Belgium and three in the Netherlands — made public so far.

The Belgian public prosecutor reported the first detentions late Wednesday, saying they concerned “possible irregularities” in contracts awarded to buy ammunition and drones via NATO.

The Belgian authorities said in a statement that NSPA employees or former employees in Luxembourg may have passed information to defense contractors. “There are indications that money obtained from these illegal practices would have been laundered, partly by setting up consultancy companies.”