The jury was told that this “victim” was unarmed. Who was it that said he was unarmed? The drug smuggler himself.
He violated his own immunity deal when he kept smuggling drugs into the country afterwards.
The agents fired when they believed him to be an armed man. Perhaps he was. Certainly his own statement means nothing as to the truth. “he said/he said”.
None of what you stated justifies two LEOs failing to report the incident involving discharge of a firearm, and then not being forthcoming when questioned about it. LEOs like this shouldn’t be LEOs any more.