No, we don't actually know that. The government has said that they were, but the government (especially the current administration) has been known to lie and stretch the truth when it suits its aims. And how is anyone going to disprove their claims?
Yeah. I'm a big believer in the Constitution. Aren't you? I'm also a believer in government accountability. If there's a trial, then We the People can see the evidence and hear any defense that the accused make, and know, once the verdict is rendered, whether the accused truly are guilty of the charges. If the government can just unilaterally declare people to be terrorists or drug traffickers and summarily execute them, how are we to know the truth? All we'll ever get is the government's side of the story. Didn't you and the rest of the Trump supporters on this site just spend the last 4 years harping on about how the government was unjustly charging people with crimes?