Threat

Me and my family was abroad and came back India last year. Previously I have issue with my mother and sister, hence after coming India I didn't contact them and was staying with my wife at her house. once we got a call from police station and told to contact S.I as he got a complaint against my wife. Later when we contact came to know that my mother give a verbal complaint against my wife and me saying that we are not contacting her didn't know where I am living and all. After 2-3 month we moved to another city in search of job and there we got another call from my mother to my wife saying that she will put case against her if anything happen to me( just threatening my wife by my mother) also she is telling everyone fabricated story about my wife. At present my wife is so disturbed and very much depressed about the action about my mother. when we were abroad, we were only looking after her, every 3month we were taking her with us, she was staying with us there. now when i lost job i couldn't look after and she is staying with my sister. i would like to know what action i can take to stop this threat and i am also worried, if anything will happen to me, may be my mother and sister will do anything to my wife,like file a case against her or something like that. i do want to make my wife life miserable. she is getting tense very fast.so much depressed. kindly suggest me