Is filling rti to wife employer is a mental harrsement?

not it is not 

What if the wife or his father files rti in my office seeking my personal information.  They have also filed several complaints in my office levelling false allegations.  The office have closed the case, in my favour.  Can it be amounted to mental cruelty and i can file for divorce?

 They have even filed complaint in police.  Right now the case is under mediation first date was on 7.1.2014.  Next is on 30.1.2014. Bail has been rejected in District and Sessions Court.

What should be my next step? 

The police case against you and threatens in any form as well as the tortures by writing to employer tarnishing the images, all constitute cruelty.  This can be ground for seeking divorce.

yas you should be prepare for divorce and ready for future legal proceeding.....