Why go through all the trouble?

To perfectly setup Evan (Correct name?) if...

You saw the uncut version, he posted the video messages online confessing. I know at this point he'd fled, but assuming he fled to another state does American law allow him to be extradited from one state to another?

If he'd fled the country, then it's more unstandable since not all countries allow extradition of criminals as I understand it.

And if you saw the cut version, it says 2 years later overwhelming evidence was found at Bill's home. Again, after going through all this trouble you'd have thought he would have at least removed as much traces as he could.

And also, why was Evan's dad instantly accusing Bill as soon as he was arrested? The only thing I could think of were the packages and from what I remember, they were addressed to Bill but sent to Evan's house? Yet still, why would this ultimately cause that much suspicion? Surely Evan's dad must also have had other reasons along with this to suspect Bill right away?