Dear Gagan
On what basis you wish to terminate the services of the employee ?
You do not have any documentation of your Terms and conditions.
Moreover, what do you mean by Dual Employment ??
If an employee is taking tuitions in the evening, does it constitutes dual employment?
What if the employee is sitting at night in the shop of his brother. Does it constitutes dual employment ?
You have to be specific.
You have to mention, what constitutes a dual employment, in your terms and conditions, so that an employee can avoid it.
Your intent seems more on TERMINATING the employee, rather than any performance issues.
How is your relationship as HR with the employee ?
What are thee feedback on him with respect to his performance and behaviour ?