Ah - this is what I was replying to when I lost the lot!
I had initially acknowledged my appreciation that people (and now you) cared enough . . . . on a second thought, given my interest in family history, I went to check for the possibility of family info on some genealogical sites. Fairly quickly, I found that the story you tell is commemorated at Find a Grave. It's free, so take a look and perhaps add your photo, which is better than the one they have.
https://www.findagrave.com/memorial/50519487/jose-maria-polancioOf course, the entry tells the tale as you have presented it, but it adds a little more detail about the disinterment by "Indians", to which you referred:
"From Texas history.com:
In Guadalupe Canyon, there are still remnants of rock retaining walls dating from 1858 lining both sides of the road as it snakes its way down the canyon. Today, those who venture down the canyon can see the headstone of U.S. Army guide Jose Maria Polancio, who served under Captain James Longstreet. Indians ambushed Polancio in this canyon in February 1855. The soldiers who found Polancio wrapped him in a buffalo robe and buried him. The Indians later returned, dug up the interred guide, stole his buffalo robe and proceeded to shoot his body full of arrows a second time."
I did not find anything definitive in my brief and shallow genealogical search, but a number of tantalising items came up relating to the name Jose Maria Polanco (note the spelling difference). For example, one of this name married Concepcion Perez at Sorocco, El Paso, on November 3 1854. Further, there was a birth of another Jose Maria Polanco on April 11 1855, in Sorocco, although his mother's name is stated to be Maria Refugio Polanco, so this brief information is problematic and crying out for further research; but there's enough here to make me wish I could pursue it - to sort out Polancio and Polanco, to check the marriage, and that birth; to see whether the murdered man's context could be significantly expanded. Was he newly married? Did he have a son born posthumously?
Captain Longstreet might also prove to be an interesting subject of inquiry.
So anyway, thanks for drawing attention to this interesting bit of obscure history.
Ah - this is what I was replying to when I lost th... (