Updated: Feb 1
This was obviously before political correctness. And before the post-fact culture of fact checks in which truth doesn't matter. I previously cited Pershing's own writing, the New York Times of the day, and now here's an except from the Scientific American of the day. (Note: Picture is used for illustration only. I have not documented its authenticity.)
The Phonograph and How it Figured in the Treaty of Jolo - Scientific American - January 23, 1904
"Polygamy is universally practiced and slavery exists very extensively. Horse stealing is punishable by death: murder by a fine of about fifty dollars. The religion is Mohammedan and as practiced on the island gives rise to many queer customs. For example a Moro without any previous preparation for calling will suddenly declare himself ‘Juramentado’, that is inspired by Mohammed to be a destroyer of Christians. He forthwith shaves his head and eyebrows and goes forth to fulfill his mission...
Shortly after Gen Bates' arrival on the island, the sultan sent word that there were some half dozen juramentados in Jolo over whom he has no control. The general replied, "Six hundred of my men have turned jurmentado and I have no control over them." Thus for the time being at least the jurmentado element ceased to exist.
Within the past few months however another juramentado has come to light. He succeeded in getting into the city of Jolo where he seized a member of the 17th United States Infantry and promptly disemboweled him. His murderer was caught in the act by a sentry on guard, who was instantly dispatched by him. Unfortunately the bullet also killed a Moro, the chief bugler of the regiment.
It was decided to make an example of the juramentado. Accordingly a grave was dug without the walls of the city. Into this the murderer was unceremoniously dropped. A pig was then suspended by his hind legs above the grave and the throat of the animal cut. Soon the body lay immersed in gore, the direst calamity that could happen to a Moro, his religion teaching him that contact with pig's blood means exclusion from heaven.
A guard stood sentry over the grave until dusk when the pig was buried side by side with the juramentado."
No, this won't dissuade the media from citing the same worthless Politifact and Snopes "fact checks" while ignoring the facts. But it's good to have an easy response close to hand.
It happened and it was documented in reputable publications of the day.