Minecraft wiki entry for Patrol, associated text: The game picks a random location 24–48 blocks along each of the X and Z axis away from the player to try to spawn the patrol's captain. If a pillager cannot spawn at the chosen position, it gives up and does not spawn anything. If the captain can spawn, the game tries to spawn 1 + localDifficulty [verify](rounded up) more pillagers, with each pillager spawning within a 4-block radius square around the previous pillager.