“I hope they don’t make any of the girls go back to the ranch,” Aly Raisman, one of Ms. Biles’s fellow Olympians, said on ESPN. “No one should have to go back there after so many of us were abused there.”

The ranch is in Huntsville, Tex., about 50 miles north of Houston, in the piney woods of Sam Houston National Forest, a popular hunting area for deer and other game. In 2001, it was designated as the national training center for United States women’s gymnastics, and, in 2011, it was named an Olympic training site.

The center played a crucial role in the building of American women into an international power that rivaled Russia, Romania and China. American gymnasts have won the gold medal in the women’s individual all-around competition at the last four Summer Olympics, and combined for gold in the women’s team all-around competition in 2012 and 2016.

Elite athletes met for monthly camps at the ranch, which was equipped with a gymnastics center, medical facility, dining and lodging facilities, but was secluded and had unreliable cellphone service. Also, families were not invited.

In such an out-of-the-way environment, Ms. Raisman told Time magazine in November, Dr. Nassar became a seeming ally, giving the gymnasts gifts and sweets. “He was always that person who would stick up for me and make me feel like he had my back,” Ms. Raisman told Time. “The more I think about it, the more I realize how twisted he was, how he manipulated me to make me think that he had my back when he didn’t.”

The ranch is owned by Bela and Martha Karolyi, the coaching couple who defected from Romania and became the guiding force of U.S.A. Gymnastics. They have not been accused of being directly involved with Dr. Nassar’s criminal behavior, but some gymnasts who trained there have claimed that the atmosphere created by the Karolyis at the ranch enabled Dr. Nassar to get away with mistreating them.

The Karolyis have said that they are not at fault.