I suspect Jane to have planted the bomb himself.

There has been much discussion about how the bomb made it into Janes house. In absence of any better way to make sense of it many have concluded, that the sheriff must have brought it in under his hat.

On the plus side hat offers a certain amount of space to hide things in, on the other that space is quite limited, especially if we choose to believe the statement about the additional concussion bomb.

The sheriff has been seen wearing that hat almost without exception, so other than the possible hiding space there is nothing suspicious about it.

Now I have discovered something I consider a better possibility for a hiding place.

There is an object hidden behind Haffner on the couch under the blanket. It is an object that wasn't there when Jane arrived at the house. It seems highly unlikely a suspect could get inside undetected with an object of that size.

This is what the sofa looked like when Jane arrived:

[IMG]http://i41.tinypic.com/10mo58k.jpg[/IMG]

http://tinypic.com/view.php?pic=10mo58k&s=5#.Ut5oQLQ1i70

and this is what it looks like behind Haffner:

[IMG]http://i41.tinypic.com/2m7ezdg.jpg[/IMG]

http://tinypic.com/view.php?pic=2m7ezdg&s=5#.Ut5owbQ1i70


There is a certain possibility Stiles was somehow involved in Janes plan. He arrives as the first of the suspects and since we don't see each individual text Jane sent out it is entirely possible that he was told to be there at an earlier time than the others.