Income sources of most terrorist organizations are based on illegal activities. These mainly include the money stolen from the bank accounts of innocent people or black money made by illegal activities. As the use of internet banking becomes more popular the frauds based on stealing passwords of some people and transferring the amount therein to mule accounts increased also. In this study we aim at detecting such transactions by establishing a Customer Trustability Index (CTI) for all customers available in the database of a bank. The CTI has a rule based component and a similarity based component based on link analysis and the RFM techniques.