We suspect someone at my wife's old job hacked into her personal facebook page and posted something. Can we press charges?

The post was made from a city she no longer works in which led us to believe it was someone in her old company. We also suspect said company because while she was employed there her personal facebook was one of the administrators for the company's fb page. She deleted the post because it made claims about her health and she was getting questioned by friends and family. We did not think to take a screen shot prior to deleting the post. We want to know if we press charges can the post be recovered and will the police be able to work with facebook in tracing the IP address back to the company we suspect? I think my wife jumped the gun and accused them on their own page of hacking their account to which they are saying that is slanderous and they could file charges. What should we do?