DAKAR, Senegal — The father of two girls kidnapped by Boko Haram was suspicious when friends told him that dozens of girls had been freed, because he had heard similar rumors countless times during the three years the schoolchildren have been missing.

But by Sunday morning, it became clear to the Rev. Enoch Mark that the news was true. The Nigerian government announced that 82 of the girls who had been taken from a school in Chibok, Nigeria, had been released in exchange for handing over as many as six suspected militants to Boko Haram.

While Mr. Mark was thrilled with hearing some of the girls were safe, his joy was mixed with the awful, gut-wrenching torment of not knowing if his own two daughters were among those released.

“We are hoping God will do something for us,” Mr. Mark said.

By midday Sunday, the released schoolgirls — some of the nearly 300 who were initially captured — had been handed over to intermediaries, taken from a town in the northeast near the border with Cameroon and flown to the capital, Abuja, where they met with Muhammadu Buhari, the president of Nigeria.