Locating MCC login with Google Client ID

[ry...@attributionapp.com]

@apiteam

Our developer who set up our adwords api access is no longer with the company and we are trying to figure out which account he used to set up the MCC for our adwords API access.  I'm the admin on the account so I should be able to get in once i know the right login, but I'm not sure what login he used.  Is there a way to find it from the google client ID used for Oauth?  Thanks!