Al-Shabaab intelligence head Abdishakur Tahliil was killed during a targeted December 29 airstrike conducted by U.S. forces just outside of the Somali city of Saakow. The mission was conducted by unmanned aircraft and used Hellfire missiles to “microtarget” Tahliil’s vehicle.

Bloomberg reports:

The U.S. Defense Department in a statement today confirmed that Abdishakur Tahliil was killed Dec. 29 near Somalia’s southern town of Saakow by unmanned aircraft that fired several Hellfire missiles at a vehicle carrying him. Somalia’s National Intelligence and Security Agency, which reported the killing yesterday, said two other senior officials of the group also died in the attack.

Tahliil “was responsible for al-Shabaab’s external operations,” according to the Pentagon statement. “His death will significantly impact al-Shabaab’s ability to conduct attacks against the government of the Federal Republic of Somalia, the Somali people, and U.S. allies and interests in the region.”

One of the most difficult aspects of battling groups like ISIS or al-Shabaab is that they’re hard to root out once they’ve gone to ground; this makes Tahliil’s death even more significant—and strategically beneficial.

Tahliil, as mentioned above, handled all of al-Shabaab’s “external operations.” According to a report by the BBC, Tahliil had just replaced the group’s former intel officer after that man was arrested earlier this week. This strategy—causing chaos within the upper ranks—has been used before. Military and African Union officials knew that when a U.S. drone strike took out former al-Shabaab figurehead and spiritual leader Ahmed Godane back in September, that his death would be the catalyst of yet another internal power struggle.

Reuters adds:

Somalia’s National Intelligence and Security Agency said on Tuesday that Abdishakur was head of al Shabaab’s Amniyat unit, which was believed to be responsible for several suicide attacks in Mogadishu.

Officials have said Abdishakur and another al Shabaab militant were killed in the attack. They have said there were no civilian casualties in the air strike.

A U.S. security official described Abdishakur as a “key operational figure” and a “senior leader” whose death would be a significant blow to the group. But the official said it was difficult to estimate what the long-term impact would be.

Another U.S. official noted that despite several deaths among al Shabaab’s leadership, the group has remained “resilient.”

The same theory rings true here, and if history is any indication, it will work just as well. The unnamed security official in the above quote is correct: Al-Shabaab defines the world “resiliant”—but it has faced setbacks, and the arrest of their former intel head is not insignificant. The group has now lost their second intel head in less than a week, which means that, unless they’re operating under a highly organized and rigid hierarchy, their ground game is going to suffer (or at least pause) until a new leader is chosen.

The African Union’s coalition ground forces aren’t perfect, but they did chase the insurgents out of Mogadishu, putting al-Shabaab on the run. If they can harness control of this brief reprieve, then perhaps they can encourage the devolution of al-Shabaab and at the same time at least hit pause on Somalia’s decades-long death spiral.