The answer to the question posed above depends upon the type of background search the employer uses. However, there are certain types of searches, i.e. Livescan, that do include information about arrests, even if such an arrest never led to a criminal case filing or the criminal case was dismissed, or the conviction was later expunged. To read more about this problematic issue, click on the following link.
http://www.greghillassociates.com/what-can-an-employer-see-in-my-criminal-history-arrests.html.