I agree. Grusch could have been misled and bought into lies/misinformation. But at the very least I think HE believes it or wouldn't be putting his career in jeopardy by reporting to Inspector Generals and testifying to Congress.
The above poster makes it sound like he is likely to be lying about it, which I think is a weak character attack and not arguing in good faith.
Don't forget, along with the oral and written testimony, Grusch supposedly provided enough evidence to the ICIG to warrant an "urgent and credible" threat.
Sounds like a pretty firm case against the alleged. Even his own mother and his daughter's mom refuted his alibi claims to police.
I'm surprised though that, according to this article, he's only being charged with fleeing the scene of an accident and not with vehicular manslaughter as well.