Background check - failing submission of docs offer would stand revoked

I made a couple of offers recently, out of which one prospective employee is supposed to join us next week. In the meantime, I've started the background check and requested him to share the documents of all three of his previous employers as mentioned in his resume. For the past two days, he has been trying to confuse me by giving different versions of stories about his past employers and has ultimately failed to submit the relieving documents from two of his previous employers which he does not possess.

I attempted to contact the HR representatives of the two companies, and they advised me to check with the candidate if he has completed the exit formalities or not. I posed the same question to him, only to end up hearing more stories. My concern is how to address this situation with him, informing him that the failure to submit the required documents is not acceptable and could result in the revocation of the job offer. Is it the right approach to take, considering he has already resigned from his current employer based on our offer?

Note: Our offer letter did not mention anything about a background check. Is it appropriate to conduct a background check with the current employer before the candidate accepts our offer?

He has not joined your company and has not worked even for a day. Therefore, you can terminate his offer.

When the candidate fails his background verification and cannot substantiate whatever experience he had claimed, you can consider him a less experienced candidate. Consequently, he would have to join for a lower salary than proposed in the offer letter.

You have two options to consider:
1. On humanitarian grounds, you can view him as a less experienced person and pay him a reduced salary. He may reclaim the original offer by providing his experience certificates in the future.
2. Alternatively, due to his false claims on his resume, which have been proven, you can terminate his offer.