Facebook/non-facebook login

Hi there,
I’m curious to know how JFBConnect handles the following use cases:
1. A user logs in with Facebook (first time registration) and then subsequently registers with her email.
2. A user registers with her username and email, and then at some later point logs in with Facebook.

Does JFBConnect know it’s the same person and therefore have only one Joomla account, or are two user accounts created for both use cases?

I have noticed at least one case of the same person with two Joomla user accounts.

Would really appreciate understanding how this works.

Thanks

Thanks much.