do these steps
1. record the threats
2. get a FIR registerd with the a police
3. hire a competent lawyer.
4 if police refuses to register a FIR due to local pressure, send a email to commissioer of chennai..things will automatically start working.
it is true that police cannot interfere in tenancy matters..but harras your tenant throuhg police via ther options..nothing to worry....just do the above and sit and watch..
in the mean time,file a eviction suit..since the tenant hahd not paid the rent..you have good chances of moving the case faster for a eviction suit -
give the tenant a impression that you have more power than him locally and being an NRI is not a barrier ..