On Oct. 7, she witnessed her parents’ murder, before being abducted. On Friday, nearly seven weeks later, she spent her fourth birthday while under captivity. And on Sunday, she was finally freed, as one of the hostages Hamas released under a deal with Israel.

Her name is Avigail Idan. Avigail, whose name has also been spelled “Abigail” in U.S. media reports, is a dual citizen of Israel and the United States, and was among the roughly 240 people, including around 10 American citizens, taken as hostages by Hamas on Oct. 7.

In a statement after Avigail’s release, Liz Hirsh Naftali and Noa Naftali, her great-aunt and cousin, said they had “hoped and prayed today would come.”

“There are no words to express our relief and gratitude,” they said, thanking President Biden and the Qatari government, which helped broker the cease-fire deal.

Avigail’s case has received wide attention, particularly in the United States, where several of her relatives are based in California. President Biden expressed relief over the news of her release on Sunday.

“Thank God she’s home,” Mr. Biden told reporters in Nantucket, Mass., on Sunday. “I wish I was there to hold her.”