It appears that you have no real "proof" and only inference. This is not likely to get the police excited. yes, you can report your suspicions to them, but without anything more to go on they may not even have enough to initiate legal action and get a subpoena for any records - much less a search warrant to his ISP or phone company to see about activity.
Change your passwords, clear your cache from your computer periodically, and make sure you have up-to-date antivirus and intrusion protection software installed. And if you share your computer, create a separate log-in for yourself that has a secure password that only you know.
There are other precautions you might take as well, but those are easy ones to do at the outset.
Also, make sure you have your account information and passwords changed at the bank and on any other accounts you might have on-line.