Finding the Lighthouse Diamond Thief

Your Background information:
It was a dark and stormy night....

when we discovered that the priceless Lighthouse Diamond was gone!   Who would have suspected that anyone could have been so clever.   We all thought it was safe and sound in our secure vault, protected by the latest high-technology.  It was even in the basement of the "You Gotta Have It - Jewelry Store" - you know, out of sight, out of mind.  That theif REALLY knew how to get around a system!
When we arrived, the thief was long gone, and the only evidence that we found was a note and a bag of white powder left in the vault.
The thief left them there to tease and taunt us!  How humiliating this has been!
In order to help solve this crime, we have decided to call you - the experts - in.   We need your professional help in solving this mystery.

We hope that you can use the evidence and some scientific thinking to solve thie "who done it".  You'll need to study the profiles of the suspects that have been named, use the evidence, then present your report in hopes of convicting this criminal. That's quite a chore - but we know that you're ready for it!
We hope we have called in the right scientific team ... YOU!
Good Luck - and be careful out there!!