Spanish Language Paper mentions Siebels Murder
The newspaper that printed this reference was located on Genealogy Bank and listed as the Prensa in Texas. I'm not exactly certain where in Texas it was published, but this reference comes from 6 January 1930.
This was located by searching on Genealogy Bank's newspapers for Haldiman, and limiting my search years to 1929-1931. It doesn't contain any real new information, but does make the point that one never knows what language one might find information in.
Siebel[sic] was actually Siebels. The German speaking family most likely could not have read this newspaper reference. It's not too hard for me to read it, but it has been nearly two decades since my high school Spanish days.