Blank cheque bounce fraud threat...mental harrasment

Hi All, My mother has taken financial help long time back in 2010 & 2012 and cleared all dues. She was asked to give some blank cheque against that trust financial support. Now from past few weeks she is mentally harassing my mother alot which has resulted effecting my mothers health. She is continuously asking people to call my mother and tell that i will produce 1 cheque worth Rs 15 Lac in her son,s account and other 2 cheques of similar amount in her relatives account. Pls suggest me what to do. We have already given her alot of amount taken as a loan from bank which can be seen in books of bank also. She was making my mother a fool and under stress my mother could not courage to tell us about that. Pls help.....Our only property is under debt of bank for 15 years and she had eyes on our property. She is a smart lady and already played with the lives of two family. Her monthly family income is almost zero and we are reputed earning family but again she is blackmailing us. Pls tell what to do..