Donna I'm so sorry you are going through this - it's one of those nightmare things you only hear about other people going through, isn't it? Yes get the police involved and protect yourself and your family.
Here are some good links to locking down your pc - hope they help you and your mom:
On a brighter note, I am almost done with my chinese auction gift (!) just need to put the clasp on. Which in reality doesn't have to be done by monday - just by the time it's time to mail it out! But I will do it sooner of course - just need to get to the LBS and buy it.