either of these "republics" into the ports of Mexico.[6]  "This silly attempt to assert the supremacy of the Supreme Government of Mexico, when they dare not set a single armed vessel afloat in the Gulf, will have no effect than to prove that the members of that Government, President and all, are supremely stupid," declared the editor of the Telegraph; "and their silly order should be styled the Blockhead's Blockade."[7]

In carrying out the terms of this proclamation and of Arista's of April 13, as well as to take alive or dead known enemies of Mexico operating below the Nueces, the historic Spanish-Mexican boundary of the former province of Texas, Lieutenant (Brevet Captain) Vicente Sánchez, aide-de-camp to General Ampudia at Matamoros, was assigned the task of eliminating the contrabandistas,[8]  and especially of apprehending Dimitt (the "principal object" of the mission). Sánchez commenced his advance towards the Nueces with fourteen men, while the Texan commissioners were on their way to Arista's headquarters to treat on the subject of ending brigand warfare on the frontier. On July 4 Sánchez, accompanied by Blas Falcón, "well known as Aubrey and Kinney's spy, travelling agent or courier,"[9]  arrived at a distance of half a mile of the Isleta de la Posa (Dimitt's Island). From here he sent forward Lieutenant Chipita with five men to reconnoiter and see if any enemy force was near, for it had been reported in Matamoros that a Texan unit of some eighty men was operating in the vicinity of the Nueces. This rumor probably had reference to Captain Price's company that had reached the Nueces on June 23. If Dimitt was found at the island, he and his companions were to be arrested and brought to Matamoros. The Mexican detail arrived at the edge of the bay opposite the island, and while they were surveying the situation, saw a boat approaching about 2 p.m., which they hailed, indicating at the same time that they were rancheros come to buy goods to be smuggled into northern Mexico. The boat was manned by William Thompson, whom Dimitt had sent that morning to the pass to purchase lumber