Repercussion if a New employee submits fake document at the time of joining

Dear Seniors,
I have a situation in my office where in a new employee joined 3 weeks ago. During employment background verification we got to know that the employee has submitted fake relieving document. Can we terminate the employee on the ground of submitting forged document? Also, is it legal if we do not provide the salary for his 3 weeks duration in office?
Look forward to your Kind suggestion.
Regards

1. What has made him/her to resort to submit fake documents to you?
2. Do you accept employee without relieving letter? If yes have you same conveyed to employee at the time of interview?
3. If genuine reasons are there then you can condone employee after issuing warning letter as per me.
4. Why you want to hold salary? By doing this do you think you will do justice to the problem?