Dear Sender
Termination is not the right solution to be used instantly
He can be adequately issued warning letters and after having documentary evidence with you, and if he misbehaves, which has been noticed evidencingly, then you can go for issuing termination letter.(that too, after considering the pros & cons)
On company's letter head
addressed to the employee-------
Dear----
Sub: Termination from the services
Consequent upon our verbal advice as there has been no sign of improvement in your performance and careerand the recent incident of your misbehaviour with our office staff, has proved that our prediction is correct. Accordingly, the management has come to the conclusiion that you do not possess good character and not willing to improve your performance. Hence management has decided to terminate your service with immediate effect on the basis of your poor performance and misbehaviour
Thanking you,
Yours faithfully
for x x x x x
Regards:
----
You can add, if you want to settle any dues to the employees, as a separate paragraph in the letter.
L.Kumar