Allow me to make a suggestion: don't just ask for information on someone. While it may not be true, such a request makes it seem that you just want someone else to do your work for you. Instead, go as far as you can and, if there is something you want clarified or checked with resources beyond those to which you have access, ask about that specifically.
That said, here are the results of a quick check. Executive Capital, LLC,
according to the MO Secretary of State, was created in 2004 by (as you say) one Clarence L. Smith. It looks as though they haven't done very much, since a google search turns up "Executive Capital" in MN, DEL and OR, but not MO. The only document your Executive Capital has filed with the MO S of S is a one-page, handwritten "
Articles of Organization". The "office address" that Mr. Smith gives is
a residence, which also appears to be the office of "
Package Boiler Service Company". There are no adverse filings against the company, but a "Clarence L. Smith" filed for bankruptcy in the EDMO is 1996 under docket 96-46047. I don't know if it is the same one, because the address is different (although also in St. Louis).