"when Patton’s forces liberated Dachau, some elements of his force became so outraged over what they had saw they started to execute SS guards before by the commanding officer stopped the executions. An investigation followed and when confronted by investigators, Patton did the right thing and stood by his men. He tore up the investigation ending it for all time. Patton was not concerned with a few dead Nazi SS guards executed by his troops"
http://iviewit.tv/CompanyDocs/United%20States%20District%20Court%20Southern%20District%20NY/Nazi%20Hydra%20In%20America.pdf
I think there was a good chance he was actually assassinated, but your point still stands.
Not familiar with this theory. Did a bit of a google, but I'm still curious to hear who you think killed him and for what motive.