Has anyone else come across a situation were you have 2 bits of evidence point towards someone, and none towards anyone else, but yet that persons albi is real?
You do need the proper smart skills to find all the evidence that may be part of your problem.
In answer to the first there is only one PE per suspect. So if you have two (one hair and one footprint for example) then it is a mistake in your notes.
There is a thread in the moderator picks that shows the "formula" for exactly what makes a person guilty or not.