Crappy ending (spoilers)

Cute movie, but I didn't like the ending.
I guess the writers felt they had to have some sort of justice, and have him get caught in the end, but I didn't like the cop framing him.

I turned to my wife and said, who did you like better in the end, the main guy, or the cop? Her answer: The main guy, of course. As much as he is flawed, he was a very likeable character.
So who gets away with it in the end?
The Cop!

No, we can't have a guy get away with murder, but it's ok to have some rouge cop, tampering with evidence, and framing guys for murder.
Think about it, He (the cop) thinks the main guy is innocent of the crime, but is willing to frame him for murder, cause he's pissed off cause he slept with his wife.

Call it karma. But it didn't sit well with me.