Which al Qaeda terrorist should U.S. target next?

Following al Qaeda in the Arabian Peninsula's (AQAP) announcement the group's head, Nasir al-Wuhayshi, was killed, questions are being raised regarding who the U.S. should target next.

While the group's newly appointed leader Qassim al-Rimi may seem like the next logical focus, former CIA insider Michael Morell said Ibrahim Hassan al-Asiri, the brains behind sophisticated bombs that have been used in attempts to attack the U.S., is "probably the most significant after Wuhayshi."

"I think he's the most important target because he is the guy responsible for producing these very sophisticated explosive devices: the one that the underwear bomber used, the one that was in the printer cartridge and the one that was in that non-metallic suicide vest," Morell, also a CBS News contributor, said Tuesday on "CBS This Morning."

An undated photo purportedly of Ibrahim Hassan al-Asiri, al Qaeda's top bomb maker. AP Photo/Saudi Arabia Ministry of Interior

Former CBS News senior correspondent John Miller called Asiri "one of the most creative bomb makers" and "one of the most dangerous people that we have seen," on "CBS This Morning" in 2012.

Two years ago, U.S. officials thought al-Asiri was killed in a drone strike, but it was later determined he was still alive.

The White House confirmed al-Wuhayshi's death on Tuesday.

U.S. strike kills al Qaeda's second-in-command

Morell said this is the most significant U.S. counterterrorism success since the killing of Osama bin Laden and is a setback for the terror group in two ways.

"One is that Wuhayshi was running the organization for 13 years. It's going to be disruptive to replace him," Morell said. "And the other is that all of these leaders now are going to have to start worrying about their own security, and that is a very good thing in terms of not allowing them to focus on plotting."

Wuhayshi was the second highest-ranking member of the global al Qaeda organization.

His branch, based in Yemen, is the most aggressive in attacking America and its allies. He put bombers on U.S. bound airliners and organized the deadly attack on the French newspaper Charlie Hebdo.

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Morell said Wuhayshi's successor, al-Rimi, is a long-time AQAP operative. The two served time in jail for about three years and broke out together.

In March, the U.S. pulled the last of its troops out of Yemen, a country now in the grips of a humanitarian crisis. Morell said this operation is a sign that although American forces left, the government is still able to obtain information.

"One of the things that's interesting to me here is that we were concerned when the United States was forced to leave Yemen that we were going to be blind, but this tells me that we have found a way to continue to collect intelligence there," Morell said.