Did the law firm provide a written release from the employee? That would be a minimum but I generally hold out for a subpoena, especially if I don't know what the action is about.
[quote user="hbarnes"]Yes they provided a written release[/quote]
That sounds like the attorney represents your employee. Perhaps you can find out what they want to know so you can better help your employee. If the employee is contemplating suing the Company, you would want to know that so you can defuse the situation or better defend (and not hand things out before discovery but be sure to obey whatever laws your state has on employees viewing their own files). On the other hand, if the employee was absent for medical care and disability due to a car wreck, you can give the personal injury attorney what he needs to know without handing over the file.
Either way, contact counsel now.