Land grabbing using fake documents.

My mother purchased a property in Khanamet, Madhapur, Telanganna was purchased from Survey of India in 1982. She has cc copies of the sale deed. Original papers are currently misplaced. Current Encumberance certificate indicating her name and other details exactly as in her sale deed. The property has been occupied by two parties, one who is the owner of the right side plot extended his boundary wall into my mothers property. The other section is claimed by another person stating that he has purchased this property from a person who is deceased.My mother has filed a case of land dispute with the area police station. I am her elder son who has served Indian Air Force for twenty years and is currently an Ex-serviceman. Protecting my motherland is my blood right however when it comes to protect my mothers land< I am helpless because people has forged documents and is trying to prove that the land belongs to them. I shall be highly grateful to anybody who can advise or suggest me what to do.