Although any lawsuit a fellow employee might bring about these allegations would be brought against your employer, you are prudent to be concerned about termination or discipline. Whenever circumstances like this arise, the first thing to do is to gather as much information as possible. This includes copies of emails/voicemails, lists of potential eyewitnesses, and your own written account of what you remember about the events in question.
Next, meet with an attorney who understands employment law and plan a strategy for how to approach the employer's investigation. Money spent to have a lawyer help you plan your reaction to this situation can save you a lot of money lost if you are fired and remain out of work.
Time is of the essence. Good luck.