By LAURA ZUCKERMAN

(Reuters) - Ultra-marathon runner Micah True, missing for four days in the rugged wilderness of New Mexico, was found dead on Saturday, police said.

True, 58, was found in the mountainous Gila National Forest in southwest New Mexico, near the Arizona border in the early evening, said Tom Bemis, incident commander with the New Mexico State Police.

Nicknamed "Caballo Blanco," or White Horse, True became a celebrity after he was featured in the best-selling book "Born to Run" by Christopher McDougall.

True left the Wilderness Lodge and Hot Springs, four miles from the Gila Cliff Dwellings National Monument, on Tuesday, and did not return. The lodge owner notified authorities on Wednesday.

Police then launched a massive search for the missing man, with 15 search teams totaling 60 people combing through 200,000 acres of steep canyons and shallow rivers in the high desert.

His body was found with no obvious signs of injury, police said. A medical examiner was en route, but because of the rugged terrain his body was not likely to be retrieved until Sunday.

True had left for a 12-mile run carrying a water bottle and wearing shorts and a t-shirt. He left his dog at the lodge.

In January, True wrote on his Facebook page: "If I were to be remembered for anything at all, I would want that to be that I am/was authentic. No Mas. Run Free!"

True was the race director for the Copper Canyon Ultra Marathon, a roughly 50-mile race that drew a dedicated group of runners to Northern Mexico.

(Writing by Mary Slosson; Editing by Greg McCune)