Newly declassified Osama bin Laden documents reveal his son wanted to avenge his father.
Hamza bin Laden, now believed to be 28-years-old, told his father in letters that "the path of jihad for the sake of God is what we live [for]," according to an ex-FBI agent.
According to Ali Soufan, the ex-FBI agent, the letters revealed also revealed a loving son: "Every look... every smile you gave me, every word you told me. I considered myself to be forged in steel."
60 Minutes' Holly Williams interviews Soufi, who was the bureau's lead investigator of al Qaeda after the 9/11 attacks, about the documents in an upcoming episode to air May 14 at 7 p.m. ET/PT.
Soufi described Hamza as the "poster kid for al Qaeda" who means a lot to members of the terrorist group.
"Al Qaeda is stronger than ever. I don't believe even bin Laden in his wildest dreams thought that he will have followers who command armies, troopslands," Soufan said.
He's basically saying, 'American people, we're coming and you're going to feel it.
'The whole things is about vengeance'
In audio messages recorded by Soufi in recent years, Soufi says Hamza aims to inspire and unite the jihadi movement to "take revenge for what you did to my father...Iraq...Afghanistan.'"