On March 24, Persifor F. Smith's brigade captured a Mexican soldier with reports that Antonio López de Santa Anna was marching an army from Mexico City to the relief of Veracruz. Scott dispatched Colonel William S. Harney with 100 dragoons to inspect any approaches that Santa Anna might make. Harney reported about 2,000 Mexicans and a battery not far away, and he called for reinforcements. General Patterson led a mixed group of volunteers and dragoons to Harney's aid and cleared the force from their positions, chasing them to Madellin.