I will answer your question with a story. And the answer to your question is yes, they can.
I was working for a major company and we were investigating a cash shortage. During this investigation, the employee in question implicated approximately 15-20 more employees who were also stealing, some in the exact way that you were. We begin our investigation as any good LP does, because if we don't and the person quits, we are out of luck. This way, we have the evidence in hand and we really don't need to talk to the employee, we just do so that we can hear their side of the story. We begin interviewing and obtain confessions from all of the employees except one. He finds out what is happening to his friends and decides to quit. Not so fast I tell him, talk to me, or talk to the police. Simple as that. He decided not to show up. I turned over all my findings to the police and they arrested him, charged him and took him to jail until his court date. The people who cooperated we worked with, he did not and he took a hit.
If you commit a criminal offense, you can be "investigated" and charged pretty much at any time.
