[LakeCleElum]

The action you take depends on where you want to end up with this. You have a wide range of options:
1) Is she a valued employee you wish to counsel and change her behavior? or at the other end:
2) Do you wish to criminally prosecute for fraud?

There is a wide range of actions in between these two. The more serious you are about taking action, the more documentation you need. At the very least:
1) Have a forensic exam done on her computer.
2) Install camera and record her actions
3) Have alarm company verify your what you suspect.
4) Make a police report and ask they forward it to a prosecutor for consideration of charges.

OR, call her in for a counseling session, explain you value her skills, confront her and ask her to explain her actions.......