LOMBARDÍA, Mexico — They have been hailed as saviors, vigilantes marching into town with military-style rifles and submachine guns, wearing no uniforms and threatening to whip miscreants as they bring order to this lawless Mexican region known as Tierra Caliente, or hot lands.

But now some of the residents who welcomed the vigilantes’ populist brand of justice, even giving them money to buy weapons, are growing anxious that these self-declared protectors may end up becoming predators themselves.

“They are all the same,” a prominent lime grower here said of the criminals and the vigilantes who have chased them out. Many of the businessmen and residents who have contributed to the vigilantes, he said, were intimidated into doing so “because they have arms.”

As the government exults over the capture last weekend of one of the world’s most wanted drug kingpins — Joaquín Guzmán Loera, known as “El Chapo,” or Shorty — the rise of vigilante groups in lawless corners of western Mexico show the pressing, and some analysts contend, deeper security challenges that remain.