The people who testified work in the same department of the government as the people who did the investigation. They are not the same people as those who did the investigation. Sanchez did not talk to the congresspeople, for example.
My point which is both clear and germane is that lying to congress about what evidence you have in investigative reports has no bearing on what evidence was presented at trial that convicted the agents.
I was going to agree with that part, but I'm not so sure. We'd have to know a lot more. The investigator controlled the investigation--all of the evidence, he interviewed witnesses, etc. If that person was not truthful in their duties, it could very well have a bearing on what evidence was presented--or not presented.
I was surprised to know that the defense was not aware that BP Agent Rene Sanchez (male) was the first point of contact of the Drug Smuggler until they heard it from the Drug Smuggler on the witness stand. Kinda curious, if ya ask me.