What is the risk here?

Scammer from Craigs list got my email name and address and sends me a legit looking check from a Wells Fargo bank in Phily.

$2700 stating I can deposit it in my account/ keep $400 and wire him back $2300 minus the fee for western union.

I called his bank and it matches the address on the check. I realize it's a scam of some sort but where is the risk for me if the funds clear and are available?

Keep the whole $2,700 ...because that's what you will owe the bank.

Contact the authorities and inform them that some guy on Craigs list is running a scam via bank wire 

Thx for the feedback. Will call authorities in the morning. I knew my bank would attach my name with some fraudulent use even if I played it dumb.
It's been a long road to recovery from a Vegas home foreclosure in 2008 and all of the shady loans the banks were offering. I had a neighbor who was a close friend commit suicide as he owned three properties and threw his last dollars at them trying to keep them alive but we both were laid off from our golf instructors job at a great country club outside of Vegas. Living the dream one minute to the worst nightmare in the next. Finally have climbed out of debt and bad credit.