|To be truthful, you need to attach some consequences to his lying or he is going to continue to provide you with more fiction. At this point, his lying has only generated discussions with you, along with the opportunity for him to concoct some kind of excuse or explanation which has shielded him from disciplinary action.|
If you truly want to put an end to this totally unacceptable behavior, you should take more definitive action the next time he lies to you. In such a situation, you should meet with him in private, present him with specific documentation that clearly proves that he lied to you, and then advise him that future fabricating can lead to termination. You should also consider putting your warning in a written document and having him sign it.
One of the cornerstones of any successful relationship, whether on or off the job, is trust. At this point, your employee is either going to get this message or another one that comes in the form of a pink slip.