The short answer to your question is yes. You can sue to have the company returned to you and possibly for punitive damages. You should act immediately to prevent the company from being raided of assets or being driven in the ground. Keep in mind that just because you can sue does not mean that you will win. However, this is definitely a case where you do not want to wait to file a lawsuit. You can also report your ex-business partner to the District Attorney's office and the Police. Whether or not the DA will bring a criminal prosecution is fact dependent on what they uncover in their investigation. Keep in mind that there are different standards for a criminal vs. civil prosecution. More evidence is needed in the context of a criminal case, so while the DA may opt not to prosecute, it does not necessarily mean that you do not have a civil case.
The above information is not legal advice and is made for general discussion purposes, and does not create an attorney client relationship.
Yes, this is criminal as well as civil. You haven't mentioned what documents were forged and whether there are any damages, but assuming this forgery caused financial damage and company you've been divested of has worth, you should hire a business litigator immediately.
If this was a FL corporation or LLC or partnership, you may need to file suit in FL, or in the state where your partner lives, if some other state. Check your company's governing, documents to see what they say about dispute resolution and which state's law governs.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.