Background checks can be run as part of a hiring or onboarding process, as permitted by law, as well as throughout the term of employment. E-Verify is only run once after an offer of employment has been made and accepted, but no later than the third business day after the employee starts work for pay. In short, E-Verify is a supplement to Form I-9; treat it similarly.
The goal of a background check is to gain insight on your applicant/employee in order to make an employment decision. The goal of E-Verify is to electronically verify employment eligibility with the Social Security Administration (SSA) and Department of Homeland Security (DHS) based on the information from a completed Form I-9.
The results of a background check can influence an employers hiring or employment decision. The results of E-Verify can not influence employment, unless if the result is a Final Non-Confirmation.
I think eVerify is supposed to match the SSN to the identity of the employee. Maybe he stole the SSN of a guy with his same name?
The problem is, e-Verify may come back with an OK for the SS number supplied, but cannot absolutely assure that the person standing in front of you is the legitimate owner of that SS#.