Open Eyes, after reading your post, I did a Google search for what you wrote: "This type of scam where you are asked to hold a check is a very common scam." Remarkably, the search took me to the website of Texas Attorney General and they accept reports of scammers:

Common Scams | Office of the Attorney General.

Since the company that wrote the check is in Dallas, I will file a report with the Texas Attorney General, in addition to the report to the FTC. This will give me some satisfaction that I acted on it. And then it will be time to move on. I agree with @Rose76 that there is no reason for F.B. to show up on my doorstep: I am no longer of interest to him.