NEAR DOHUK, Iraq -- Ayham Elias is an 8-year-old Iraqi boy who made it back from territory held by the Islamic State of Iraq and Syria (ISIS) in November, more than three years after he was kidnapped by the extremists. But when the little boy arrived in a muddy refugee village near Dohuk in northern Iraq, his family immediately noticed a change; Ayham had somehow learned to speak fluent English.

He says he lived under ISIS rule with an American family. He only knew they were American because the woman told him she was from the U.S.

Ayham tells CBS News correspondent Holly Williams that he spent two years living with the American woman and her four children in Raqqa, which was then the ISIS self-declared capital city in Syria.

Asked what the woman's name was, Ayham said he called her Umm Yusuf, but that her real name was Sam.

Amazingly, an ISIS propaganda video released in August seems to confirm much of his story. It shows Ayham with a boy he identifies as Yusuf -- whom he says was the American family's oldest child.

He says the family treated him with kindness. They were forced to make the video by an ISIS gunman, he tells CBS News.

Ayham is a member of the Yazidi religious minority, which was ruthlessly targeted by ISIS as the militants rampaged across Iraq in 2014. Yazidi men were killed and women and children were kidnapped -- the women later sold as sex slaves.

Ayham tells CBS News he was separated from his mother -- who is still missing -- and beaten before he was handed over to the American woman named Sam.

Her husband, a North African man, was killed by an airstrike, Ayham says, as the U.S. coalition pummelled Raqqa to eventually help regional forces retake the sprawling city.

"All the night they're bombing our house," the young boy recalls. "All the night."

Ayham fled ISIS territory with the American family, he says, but they became separated, and now he misses them.

"I want to go next to this woman," he tells Willams. "Next to this family. American. American family."

It's an extraordinary story, but the woman he knew as Sam remains a mystery. CBS News has not been able to confirm her identity, or her U.S. citizenship. We don't know how she ended up living under ISIS, or where she and her children are now.