> Find a lawyer, ASAP, that specializes in employment and / or IP. This is a legal issue and you need to solve it with people that know the law. Talking, signing, admitting things, etc, only hurt you.

This. Anything you say. Anything at all. Can. And will be used against you in a court of law. Your job wants your code. Personally I would lawyer up and start applying for new jobs elsewhere and ensure they wont pull the same. Just never work on code from their hardware on their resources (internet, power, etc).