Spoilers for Riverdale episode "Chapter Thirty-Three: Shadow of a Doubt" ahead. This episode pierced a hole into a highly discussed Riverdale fan theory. The show suggested that, despite his daughter's suspicions, Hal Cooper is not the Black Hood — because he can't be in two places at once. See, after the Black Hood attacked a Hermione Lodge campaign event where one Hal Cooper was seen in attendance and not in a hood, it seems impossible that Betty's dad could still be the Black Hood on Riverdale. However, much like Fred Andrews survived the shot that kicked off Season 2, the theory that Hal and the Black Hood are one and the same is still alive and kickin'.
Being shielded by her father while being shot at by the Black Hood seems like it should be enough to convince Betty Cooper that her father isn't guilty, this amateur detective still was not sure. After all, a brief investigation with Cheryl into her father's "ShareB&B" revealed an old copy of a Nancy Drew codebook — the same codebook that had been used to encrypt the Black Hood cyphers. When confronted about the book, Hal explained that it was intended to be a gift, since Betty would always get it out of the library when she was a kid. Hal's excuses seem pretty solid — until you consider the possibility that there is more than one Black Hood.
The Black Hood appears to be an adult man with green eyes and that's really all that anyone has to go off of. While Archie may think it's useful for him to be going door-to-door looking into people's eyes trying to hunt down the Black Hood, he's acting under the presumption that no one else in the entire town of Riverdale could don a black ski mask and wield a gun. In reality, many of the crimes committed by the Black Hood don't have people talking about their bright green eyes, and it's only Archie who seems to be obsessed with that detail. Hal Cooper doesn't have bright green eyes, but there may only be one Black Hood that has those eyes.
Just because Hal Cooper wasn't acting as the Black Hood at Hermione Lodge's campaign event doesn't mean he wasn't the Black Hood who shot Moose or killed Midge, or is acting as the Black Hood to bring out the inner darkness in Betty Cooper. Archie and his fellow amatuer crime solvers already learned this lesson the hard way when former janitor Mr. Svenson took the fall for the "real" Black Hood, seemingly put up to the task of wearing his outfit to terrorize Archie Andrews without putting the real Black Hood at risk. Once you accept that there is likely more than one Black Hood, Hal's alibi falls apart and he once again becomes a primary suspect.
The question that has been asked all season has been "Who is the Black Hood?" when people should really be asking "Who is a Black Hood?" It's much easier to stop one person from killing others in Riverdale, but the true nature of those who don the Black Hood may be more complicated than that. Wearing a Black Hood allows Riverdale's citizens to act on their darkest impulses including stalking, intimidation, and murder.
At the end of "Chapter Thirty-Three: Shadow of a Doubt," Betty set up a meeting with her father and it seemed that she was hoping to finally confirm or deny once and for all her suspicion of him being the Black Hood. Even if Hal has been acting as the killer, stopping him may not stop another Black Hood from popping up and wreaking havoc on Riverdale. However, if Hal Cooper has been using the Black Hood to terrorize her daughter and scare off Chic Cooper, his reign under the mask could be coming to an end — because Betty is 100 percent done.