The Trumpeter Taken Prisoner
The trumpeter in the story may be considered innocent. After all, he hasn’t killed anyone. His responsibility is to only blow his horn during the presence of enemies. However, his post is very crucial to the success of his team.
The other group was right. By sounding out the orders, the trumpeter guide and encourage his soldiers in battle. That being the case, he was instrumental to the death of hundreds of soldiers of the other camp.