Everyone is being fooled

According to Molly Brown (Debra), episode 7, "Plot Twist," was only half of the real plot twist. I personally believe the captain isn't the killer, so hear me out:

In the same episode, Sofia judges Dexter because she thinks he cheated on her based on the evidence she had. I think this was purposely written to show how viewers might judge the captain/dexter would judge him. Remember, this is a younger Dexter ,ust because he thinks something is true doesn't mean it is. Then, we have the scene with Dexter talking about the captain being the killer, followed by the last scene with the captain. Why are they overexposing the idea that he is the killer? Because they want us to believe it.

What about the hesitation when the finger was cut?

It’s simple ,that guy was stabbed,and he was also cutting a kid's finger. Isn’t it crazy to think he would hesitate, especially that was the second kid