Dear friend,
There is no mention in the post what the duration of the period of probation was and whether the employee was officially confirmed on the post for which he was selected OR was undergoing probation before the termination based on back ground verification. If he was only a probationer, the action of the management in terminating his services based on any negative feed back in the back ground verification report without assigning any reason or notice as per the terms of the contract of employment might be correct. If not, the management ought to have at least mentioned the reason for the termination in the orders for it can be construed as a declaration to the effect that never the individual was appointed since he has procured the appointment by means of submission of fake documents or suppression of certain vital facts as the case be and not an orders of termination in the normal sense.
Coming to the issue of with holding of 45 days salary in a total length of 75 days service, it is certainly illegal. Salary is the compensation payable for the services rendered. Hence it is the automatic right acquired by the employee for remaining under the services of the employer subject to his directions and disposal. Thus, salary is first earned by the employee and only then becomes payable resulting in the fulfillment of the mutual consideration of the contract of employment. Therefore, the employer has no right to with hold the salary for the duty period.