Why does Quinn give up on catching Dexter?

Question

In season 5 of Dexter, Detective Joey Quinn is heavily suspicious of Dexter and what he gets up to. Joey then hires Liddy to spy on him. Liddy gets some good evidence including pictures of Dexter and Lumen going out on his boat to dispose of a body. Dexter kills Liddy and its fairly obvious to Quinn that Dexter must have done it.

Blood is discovered on Quinn he gets brought in to be questioned. Quinn eventually gets released, but basically gives up in his pursuit of Dexter. Why is this? Is it just because he doesn't want to upset Debra? (I'm on season 6, so I'm unsure if this issue resurfaces in later episodes.)

Answer 1

If I remember correctly, Dexter tests the blood on Quinn but provides falsified results stating that the blood is not Liddy's. Quinn realises that Dexter is getting him off the hook and then more or less lets Dexter off.

There is no hint that the suspicion has gone away, but that he accepts that Dexter is not all he seems, but trusts him.

Answer 2

If I am correct, Quinn quits catching Dexter more because of Debra's fight with him rather than falsify blood test report which saved him.

He loves Debra and when they had fight on Dexter's matter, he started ignoring Liddy. Even when he got arrested he doesn't mentioned anything about catching on Dexter and what's Liddy working on. So it's clear now that Quinn is now more concerned in getting Debra back rather than catching Dexter.

Answer 3

Dexter also catches Quinn stealing money from a crime scene. That puts him on the back foot already. Dexter goes ahead and does Quinn one when he fudges the blood one Quinn's shoe. If Dexter had not done this, Quinn would be history! Besides he's dating Debra and thinks that dexter is a decent guy after all. so it would simply make sense to stop bothering dexter.