Are you a thief though? Really? From reading your post it sounds like maybe you were a thief. Are you still stealing today?
You are not whatever mistakes you have made in your past, no matter how awful they may seem or be: they do not define you and you have the power to not let it control the rest of your life.
Frankly, we are all to some degree a mixture of bad and good. Focus on being the best you that you can be today, and think of how you want to be even better in the future and work towards it.
It sucks when people around remind us of who we were, but the best apology is always changed behaviour I think.
Is it possible to look for a new job, if they make it really unbearable, or do you like it apart from their comments perhaps? There are ways out. If you want to or have to stay in the job, try to even fake it to not let them see it getting to you.
Is HR aware? It's hard to advise in a general way but just know we are here if you want to share anything further, and you have us supporting you to be a better you.