Estranged stepmother

Multiple marriages and inheritance My father was married twice. The first wife left him some 33 years ago and my mom took care of my dad until his last breath. We are the family from the second wife. They have a girl from their first marriage, who is now already married and have kids. I am the only son of the family and we are from Assam. The property is under my name however, I got a call from my dad’s estranged wife claiming for inheritance property. The estranged wife cameonly for the 13days ritual which now makes us think that there was some motive behind it. My dad bought a small block of land for my step sister (estranged wife’s daughter), and we spent a lot of money in her wedding. In fact, I paid off the loan that was drafted for her wedding. My dad and his first wife separated some 33 years ago (no divorce), she left the house and never returned, however my mom used to send them money every month, for my step sister’s tuition fees and to cover the cost of living. My question is, can she still claim rights in our property?