Mental illnes just after marraige ?

Hi, I got married 2 months back. After our wedding reception we notice that girl was suffering from mental illness. We reported to their family but they said either she is doing Drama or due to pressure of marriage her behavior is not normal. We believe that and tried to give some time when we saw no improvement in her mental condition after one week we went to a doctor and doctor gave the medicine, but there was no improvement in her mental problem. Again we went to another doctor he prescribed medicine but no improvement. After one month we took her one of famous mental doctor and as per mental record it shows the disease is from 10 years and disease is "Mood Disorder". After two months we did not see any improvement and we sent her to her parents’ home. Now her parents is blaming us for her mental illness and threating for false dowry case. We have video recording and audio recording of her unusual behavior right after marriage. What evidence i need collect to prove we are innocent and girl was suffering from mental illness prior to marriage? How can prepare myself to prove that we are innocent and we have been cheated by in law ?