U.S. intelligence agencies said they were "80 to 85" percent sure of his death, though bin Laden's body has yet to be recovered for DNA testing.
He was "in the wrong place at the wrong time," and was not targeted an intelligence source told NPR.
"We make a big deal out of him because of his last name," the official added.
Meanwhile, papa bin Laden has eluded capture for nearly a decade since masterminding the 9/11 attacks of 2001.
Osama's other son Omar recently co-wrote a book with his mother titled "Growing up bin Laden" about the family business.
In the book, Omar writes that his relationship with his dad -- the world's top terrorist -- fell apart when Osama gassed Omar's puppies in a chemical warfare experiment.
"After I learned the truth about the puppies, I turned even further away from my father," he wrote.