Osama Bin Laden
Osama bin Laden is shown in this video frame grab released by the US PentagonReuters

Osama bin Laden's son Hamza may be set to lead Al-Qaeda, a former FBI agent recently told a TV news channel. The investigating agency's former official said that they had seized certain personal letters during the raid which killed Osama, and found out that the terrorist leader's son was poised to lead the terrorist group.

The letters were collected in the raid conducted in May 2011 by helicopter-borne US Navy SEALs at a secure high-walled compound in Abbottabad, a garrison town north of the Pakistani capital, Islamabad.

The former FBI agent, Ali Soufan, had led the investigation against Laden after 9/11 attacks. Soufan, in an interview to CBS news, said that Hamza, who adored his father and wished to carry forward his ideology, will take over as the next leader of the outfit to avenge his father's death.

Soufan added that Hamza wrote those letters to Osama when he was 22 years old. The letter mentioned, "I consider myself to be forged in steel. The path of jihad for the sake of God is what we live." The content of the letters are now declassified.

The former agent also added that Hamza, who is now 28-years-old, can unite the jihadist movement of Al Qaida. Soufan told the news channel that they found several similarities between Osama and his son.

hamza bin laden
Picture taken from undated Al Jazeera television footage purportedly shows Hamza bin Osama bin Laden (L), one of the sons of Saudi-born dissident Osama bin Laden, displaying what the Taliban say is wreckage from a U.S. helicopter near Ghazni.Reuters

"His recent message that came out, he delivered the speech as if it's his father...using sentences, terminology that was used by Osama bin Laden," Soufan said. The US recognises Hamza as "specially designated global terrorist," and has been given the same classification his father once held, Soufan told reporters.

Soufan also said that Hamza has recorded two audio messages in the last two years.

"He's basically saying, 'American people, we're coming and you're going to feel it. And we're going to take revenge for what you did to my father...Iraq...Afghanistan'...the whole thing was about vengeance," Soufan added.

Soufan, in a new episode of 60 Minutes on the network, described one of those letters from Hamza as: "He tells him that...he remembers 'every look...every smile you gave me, every word you told me.'"