Wife went to parents house with child without informing not returning

My Wife is an architect with LNT and was working out of Puri, Odisha. her parents brainwashed her mind and made her to take a transfer back to Kolkata where her parents reside without my knowledge along with my 18 month old son. I am a Hindu. My in-laws are all into business whereby, they show income tax of 1 lac per month but have incomes above 10 lacs. Also they are very low standard people with no one expect my wife are graduates. When I came to know that my wife has escaped without my knowledge to her parents home, by brother in-laws threatened to kill me in case I went to Kolkata or their locality. On the other hand, in my family, my father is a retired Commissioner of Customs and GST department, I am a B.Com LLB graduate but not a member of the bar council, My younger brother is an engineer and passout of IIM Kolkata. It my child stays at my in-laws place the future of my child will be ruined. He will become an anti-social just like those in my in-laws house.