Child custody

Respecterd sir i was married in year 2003 december and had a baby boy out of wedlock in year 2005 but in thear 2008 my wife left her matrimonial home with my son and all her stri dhan and in year 2011 filed i flied a rejoinder case along with custody of my child. i was denied the custody and she counter filed domestic violence case against me and my family members, after years of passing we agreed for mutual divorce and i paid 15 lakhs in a way of a fd named in my child name and rest 3 lakh was to paid when moving in second motion of mutual divorce but to my surprise ifound out that my son is being physically tortured by my wife and her parents and also being mentally harresed so he may become mental or suffer to his last days as the nominee in the FD is my wife. All the neibours has confirmed the brutality act my inlaws and even filed for the same with local police. i have also not filed for second motion as i fear for my son life and now also the time barred for the second motion. Pls help me and suggest apporipitate ways to save my son life. helpless father