Can a FI use posts and/or comments made by a customer on a social media outlet to aid with their Reg E investigation?

You can use whatever information that you can legally obtain to aid in your Reg E investigation.

Considering that social media is public information, I was thinking I could but I wanted someone else's input besides my own to ensure I would not be out of context in doing so. I would appreciate any other comments if anyone has any. Thanks BrianC

I agree with Brian. Reg E requires you to conduct an investigation but doesn't tell you what you can or can't do in your investigation. It would seem to me that using public information to reach a conclusion would be a reasonable approach.