Friends: American who joined ISIS was "one of the guys"

American ISIS member being interviewed by FBI... 02:00

WASHINGTON -- Many of the Paris attackers were French citizens who joined ISIS in Syria and returned. This week, an American who joined ISIS surrendered in Iraq.

Mohammad Jamal Khweis is one of the few American ISIS foreign fighters we know of to walk out of ISIS-held territory alive.

"I didn't agree with their ideology," Khweis explained in an interview with Kurdistan24.

American ISIS fighter says he regrets joining... 02:24

He is now a prisoner of the Kurds and being interviewed by the FBI -- a world away from the Washington D.C. suburb where he grew up.

Khweis said his parents emigrated from Palestinian territories. His father, a limo driver and said he has spoken to the State Department and the FBI.

Kweis graduated from Alexandria, Virginia's Thomas Edison High School in 2007, where friends described him as a normal guy.

"He wasn't someone who was an outcast or something like that -- he was one of the guys," Harrison Weinhold told CBS News.

Weinhold said growing up, Khweis was known as "Mo" or "Mike."

"There wasn't anything that would lead me to believe that this was, like, on the radar, that he was just going to go join ISIS," he said.

More details on American ISIS defector captur... 02:12

But Kweis did join ISIS -- and now investigators want to know how and why.

U.S. authorities said in December of last year, Khweis left Baltimore Washington International Airport for England. From there he traveled to Amsterdam and met a woman who took him to Turkey, where he crossed the border into Syria.

He said a month later, he decided life with ISIS wasn't for him and fled.

"Our daily life was basically prayer, eating, and learning about the religion for about eight hours," Khweis said.

Khweis told Kurdish television he did not see other American foreign fighters.

The FBI will want to know about the network that got him there. U.S. officials said they will take their time debriefing him before charging him.