Could the evidence have been saved?

Even though Noah stood up and screamed he was guilty, that shouldn't have stopped the detective's testimony of the evidence he found from being heard. Not to mention it's suspicious of someone to scream they're guilty just when a witness is about to present evidence. I'm surprised nobody followed up on that and let the detective present what he found at the scene despite Noah's confession because a confession doesn't prove anything especially when it's made at a very critical breakthrough in a case. They shouldn't believe he was genuinely confessing after he spent months saying nothing, bribing the mechanic for silence about his car, and going through this trial business until he suddenly confesses before a witness is about to present a big discovery. Confessions like that should be investigated on when they prevent a big testimony from coming forth.