Famed ultrarunner Micah True has been found dead in the New Mexico wilderness after a four-day search. He had set out on a 12-mile run last Tuesday in the steep canyons near Gila but never returned. A search party found his body Saturday evening. The cause of death was not known and there was no sign of trauma on his body, authorities said. True, 58, had gained fame as the central character of the non-fiction book Born to Run. The 2009 tome, penned by Christopher McDougall, examined the sport of endurance running among New Mexico's Tarahumara Indians and became a surprise best seller. Known as Caballo Blanco (or "White Horse" in Spanish) True favored distances of at least 50 miles that traversed steep and rocky trails which he would invariably run in sandals. He was also the director for the Copper Canyon Ultra Marathon a 50-mile race which is held in the New Mexico wilderness on the first Sunday of March each year. More than 500 runners participated in this year's race, which marked the event's tenth anniversary.