Two of your men had brought in someone; Colonel König.

He was out cold, and had a little blood on him here and there. He tried to fight your soldiers, but he soon lost. Being struck against the head with something blunt.

They brought him to you because they apparently saw him snooping around, and mapping out the outside of your base. You went ahead and tied his wrists to a rope that was hanging from the ceiling, forcing him to always stay standing even while unconscious.