Many Texas Rangers, including Company B, were ordered to secure the areas near the border and to stop raids by bandits, Villistas, and Anglo-Americans trying to provoke conflict with Mexico.

The Plan de San Diego was a manifesto made by two Texas Mexicans in an attempt to create an uprising against Anglo-American settlers in the lands acquired by the US after the Treaty of Guadalupe Hidalgo following the Mexican–American War.

Although unsuccessful, this plan spurred fears of more violence in the border states, in addition to banditry and the encroaching Mexican civil war.

[2] On January 26, 1918, Texas Rangers Company B, under the command of Captain James Monroe Fox, entered and searched the homes of villagers in Porvenir after suspecting involvement in the Brite Ranch raid a month before.

Shortly after two of the men returned to Porvenir, the Rangers reentered the settlement in the early hours of January 28, taking everyone out of their homes.

[5] A total of 15 males, two boys and the remainder of the men, all ethnic Mexicans, were separated from the women, other children, and Anglo-Americans in the village.

The massacre was characterized in the paper as "trouble with a band of Mexicans...supposed to have been implicated in the Brite raid ranch."

The paper did report that the U.S. State Department, at the urging of Mexican Ambassador Ignacio Bonillas, had ordered an investigation, tasking the military in the Big Bend District to conduct it.

[7] The El Paso Herald on that same day reported that the Mexican men killed were all wearing clothing from the Brite Ranch store; this was countered by acting Mexican Counsel General Ruiz Sandoval, who noted that everyone in the region bought clothers from Brite Ranch.

On March 25, two months after the Porvenir massacre, a rancher and a female Mexican servant were killed by raiders at nearby Neville Ranch.

The 1919 joint Senate–House investigation concluded that the Texas Rangers had committed many atrocities and extrajudicial killings, particularly of ethnic Mexicans.

The investigation largely ended the mass violence by law enforcement against Mexicans and instituted a new level of professionalism within the Rangers.

[14] In 2015, archaeological research at the site of the killings turned up bullets and casings likely to have been fired by US Cavalry standard-issue weapons.

One of the team's archaeologists, David Keller, said, "I can say with a fair degree of confidence that the artifactual distribution, the types of artifacts, all strongly conform to the hypothesis that this was the site of the Porvenir Massacre of 1918.