The mystery of the Chinese Paralympic champion in the New York City Marathon took a while to unravel.

The champion, Zou Lihong, was supposed to re-enact a great showdown from the Rio Games, where she beat the favored American, Tatyana McFadden, by a hair in the wheelchair marathon. But when McFadden crossed the Central Park finish line as the champion on Sunday, she hadn’t seen Zou for miles. None of the competitors had. Questions to a race official yielded no clue as to what had happened.