HYDERABAD, India — She was awarded one of India’s highest civilian honors, brushed aside a fatwa issued against her and has traveled extensively despite threats to her safety, but on a recent Monday, Sunitha Krishnan looked a bit unnerved.

A few days earlier, several women posing as sex trafficking victims engineered an attack at a shelter Ms. Krishnan oversees about 35 miles from her office outside Hyderabad, in southern India. The women stormed a nursery filled with babies, smashed windows and stabbed staff with shards of glass, injuring a few of them seriously.

At her desk, Ms. Krishnan recalled a sobering moment after learning of the attack.

“As I was sitting here,” she said in an interview, “it suddenly sank in my brain: What if one of the children — ” She broke off. “What if one of them is hurt? I crashed completely. I was crying and crying and crying.”

By “God’s grace,” she said, none of the babies were injured.

For over two decades, Ms. Krishnan has led Prajwala, an organization that rescues women and children from sex traffickers in Hyderabad and across India. The stories are horrifying. During a TED Talk, Ms. Krishnan spoke of Shaheen, a toddler who was found near railway tracks and had been raped by so many men that her intestines were outside her body.