How to resolve issue relating to sales deed

Somebody has done sale deed and claiming our property saying my mother sold him, I come to know after her death. We have 13 decimal of land mutatated in 1968, whereas his deed reflecting 33 decimal in plot & khata nos. How can my mother sold more than record property & she has not sold I confirm. My mother age was 70 when sale deed processed. Tomorrow DC has case hearing of the subject. Is the party can be bought under criminal case under jurisdiction. Is submitted 33 decimal tax receipt during registry will help me for forgery case.