I think Laguerta wins this easily.
Who do you think is the most morally repugnant character that fans tend to defend?
SpoilerSpoilerHe isn't screwing with evidence from the beginning - he does do that later on, with terrible consequences, that is true. However, we're shown early on that his usual type of victims are those who wouldn't be convicted in court and who therefore are perfect for his table.
For example, the priest in the first episode who sexually abused and then murdered little boys - how many more victims before there's enough evidence to convict him? What about Chino, the guy who never got convicted because the witnesses were too afraid to speak up? What about Jorge Castillo and his wife Valerie Castillo, the immigrant smugglers who murdered those who couldn't pay - who would have denounced them to the police? What about the one who was repeatedly drunk driving and causing fatal crashes, who was acquitted in court? What about the pedophile preying on many children, including Dexter's - how long would it take for him to be convicted for good? Etc
In season 2, we learn that Dexter had a bad blood report on one of his victims. And it was bad to the point that it was obvious and that's when Doakes searched Dexter's apartment.
So yes, he was screwing with evidence from the very beginning. He was letting killers walk basically his entire career. They just didn't show us that until season 4, but they implied he was doing it very early on.
If you’re talking about episode 7, wasn’t he intentionally trying to make Doakes look bad by giving him a bad report, and then telling his superiors the real thing, therefore making Doakes look like an idiot? I don’t really see how that proves that stopping the police from catching killers is something he does often… in most of the cases we see, the police were unaware of the killer, or they couldn’t get enough evidence on them, and by following the justice system Dexter would likely never be able to convict them, due to the way he found out they were killers (illegally collected evidence). In some cases, he did make that mistake - like with Trinity, and it cost a lot - nonetheless that definitely doesn’t seem to be a majority of the cases.
Lundy calls Dexter out for a bad blood report which Dexter first tries to defend, then blames in overwork. But the truth was he intentionally let the guy walk so he could kill him. So Dexter has been doing this all along.