I'm being sued by a former subordinate in a wrongful termination case. I don't work for that company anymore, must I take part in the case.

I was the supervisor for this person from 3/14/14 until 9/30/15 when I left the company. A new supervisor took my place and carried out the termination but the new supervisor was not named in the case. This happened in Sacramento, CA and I now live and work in Ohio. There was no doubt that my supervisor did not like this person and wanted to get rid of the employee. The employee thought that I was out to get them but it was my boss who had me change a yearly evaluation in order to build a termination case against this person and this was one of the reasons that I left the company. By me being in Ohio, do I have to take part in this case because the paperwork was sent to my old California address.