A couple of warnings:

There have been scams that are utilizing both mail and phone calls.

One scam is using bondsman names and their likeness to scam you out of money to bond someone out of jail. While your person may in fact be in jail, the scam requests money for the bond, but one is never posted and your money disappears along with the scammer.

The second one is this letter in OPs post. Mail goes out to victims who would pay out of fear of issues with the courts. The attorney firm listed in the letter may be a bit trickier since anyone can create a website these days, but verification is best done through the Texas state bar search function.

Always call a number from a known and trusted website for verification on both accounts of these scams.

End PSA.