During Mission 3 of Sniper Elite 5, there is a building in the northern part of the island that serves as a Spy Academy and it involves a side quest from the very mission. When needed, you can open our guide and learn where to find the Spy Academy building on the map, the location of the instructor(mission target), and how to kill him in order to stop further spy training.
Finding the spy academy
At first, the quest doesnt appear in your journal. For it to find its way to your log, you must reach the Spy Academy building or eavesdrop on a conversation between two officers which takes place in the course of completing the main objective of the mission.
The building in question is located in the northern part of the island, not far from the monastery - looking at the attached screenshots will help you find it. The Spy Academy is guarded by numerous enemies, but you don't have to eliminate them all.
Stop the spy training
The instructor sticks to the lower floors of the building (the search area is marked by blue) and the easiest way of reaching them is sneaking from the northern gardens. You can take care of all encountered officers and approach the corpse, or use your binoculars to confirm the kill. Murdering the instructor completes this short side assignment.