Agustín de Colina, a Franciscan priest, was stationed in 1687 at the struggling missions of La Junta de los Ríos (the juncture of the Rio Grande and the Río de Conchos), at the site of present Presidio, Texas, and Ojinaga, Chihuahua. There in the fall of that same year, widely traveled Cíbolo and Jumano Indians approached Colina and asked him for a letter that they could take to "the Spaniards who were coming and going among the Tejas" in East Texas. Not privy at this remote location to intelligence that Frenchmen had landed somewhere on the northern Gulf Coast, Colina made light of the request and countered with one of his own: the Indians should bring him a letter from "the other Spaniards."
In September 1688 five Cíbolos who had just returned from a journey to East Texas brought news that a "Moor" lived among a tribe situated near the Tejas. The foreigner was Jean Jarry, a Frenchman who had likely been a member of the Sieur de La Salle's colony at Fort St. Louis. Shortly thereafter, other Cíbolos arrived with details of strangers living among the Tejas Indians who had armor and long muskets. These foreigners were assuredly La Salle's men.
Colina reported this information to Juan Isidro de Pardiñas, the governor at El Parral. Pardiñas felt obliged to investigate the matter, and on November 3 issued an order that led to the formation of an expedition commanded by Gen. Juan Fernández de Retana of Presidio de Conchos. The Fernández expedition, however, was repeatedly delayed by Indian unrest in the La Junta area, and it did not depart for the land of the Tejas until sometime later.
Despite the joint efforts of Colina and a fellow priest (Joaquín de Hinojosa) to missionize the Indians at La Junta de los Ríos, conditions among the enemy nations of the locale forced them under orders from their superiors to abandon the fledgling missions and withdraw to Fernández de Retana's presidio. Both priests gave testimony before the departure of a military entrada that inflicted punishment on some of the offending Indian nations. Subsequently, news of the destruction of La Salle's colony reached Pardiñas at El Parral. He reacted by canceling the Fernández expedition, which had advanced as far as the Pecos River before returning with Chief Juan Sabeata and news of its own that the French settlement had been destroyed. After depositions at El Parral by Sabeata and other Indians, Pardiñas ordered General Fernández to return to his presidio. It is possible, but by no means certain, that Agustín de Colina continued to labor as a missionary in the La Junta region.