Fraud pmla

A private limited company. Owned by 2 families. 
Family A and family B. Head of Family B is managing director with 40% shares. Family A is majority shareholder 60%. Family A never enquired MD about the company for 8 years. F (A) Fulli trusted Family (B). Now after 8 years when F ( A ) inquired about the business. It was found of fraud of huge amount. How to prove it that F (B) did fraud ?

 It's true. Any knowledge, feedback highly appreciated.