This is the first Monday that I am doing a Mystery Theme and it features TEXAS mysteries. This is NOT an original idea and I want to give credit where credit is due.
At work on Fridays' we started off with coordinating our shirt colors on Fridays. Now we are coordinating themes for our shirts on some Fridays - like Dallas Cowboys, Mardi Gras, United Way ... just to name a few.
Also I know other Blogs have special days of the week like a friend at http://jenningsjunk.blogspot.com/ that she calls Whensday. It is one of her way of posting pictures and memories.
Rather than try to list authors who write in this theme category, I will give you a link (or two) where you might find a list that already exists. There is no need for me to reproduce the work when somebody has already done it.
Texas Mystery Authors http://www.texasmysteryauthors.net/
Lone Star Sleuths http://alkek.library.txstate.edu/swwc/exhibits/mystbib.html
The Cozy Mystery List Blog http://www.cozy-mystery.com/blog/mystery-books-that-take-place-in-texas.html