Can my boss demote me after I have filed an affidavit implicating him in a harassment suit?

I reccenty signed an affidavit implicating my boss in a harassment suit. Since then he has threatened me, told me i could not afford to be involved, and told me that know one will believe me. I signed a second affidavit after he threatened me last Wednesday. Today he demoted me saying i wasn't fulfilling my job requirements. I have never even been written up or told that i was doing a poor job. The harassment suit is taking place at the same time as a fight for control of the company. I do not have an attorney. I signed the first affidavit because it was the truth, he is harassing people, and i feel that it is wrong. I know that his behavior is inappropriate but i don't know how far i should take it.