[4] In late-December 1856 or early-January 1857, Flores attempted to pursue and rob a wagon traveling from Los Angeles to San Juan Capistrano.
Missing the wagon somewhere on the road, Flores instead led a group of outlaws on a raid against San Juan Capistrano looting the shop of a local Russian-Polish merchant Michael Krazewski.
[5][6] They had been after an informant who had previously testified against him for horse stealing years earlier and, when the man was able to escape before their arrival, they proceeded to loot the town and spent the night "in drunken revelry" until leaving sometime around 2:00 am.
The posse headed south, resting for the night, before stopping for breakfast at the main house of the Rancho San Joaquin southwest of the present-day Santa Ana.
Don José Antonio Andres Sepúlveda, the ranch owner warned the men that they were extremely outnumbered and should get reinforcements before continuing their pursuit.
Members of Flores' gang were hunted down in Los Angeles and authorities organized a Los Angeles posse that included 51 American merchants and Californio ranchers, Manuel Cota the Temecula leader of 43 Luiseño scouts, the Monte Rangers former Texas Rangers and members of the vigilante gang the "El Monte Boys" led by Dr. Frank Gentry and Bethel Coopwood.
The Monte Rangers moving to cut off escapees, captured Flores and Pancho Daniel after a shootout, but they managed to free themselves and escape that night.
With "practically every man, woman and child present in the pueblo", numbering an estimated 3,000 people, Flores was tried at a public meeting for murder, condemned by vote and hanged near the top of Fort Hill in what would later be present-day downtown Los Angeles on February 14, 1857;[10][11] Addressing the crowd from the scaffold, he stated "he bore no malice, was dying justly, and that he hoped that those he had wronged would forgive him".
"[14]"Tapía's case was rather regrettable, for he had been a respectable laborer at San Luis Obispo until Flores, meeting him, persuaded him to abandon honest work.