Story highlights The U.S. believes they have killed a man whom many analysts consider to be ISIS' No. 2 in command

The killed ISIS leader goes by several names, including Hajji Imam and Abd al-Rahman Mustafa al-Qaduli

(CNN) The Pentagon said Friday that it had killed ISIS' finance minister, Abd al-Rahman Mustafa al-Qaduli, whom many analysts consider the group's No. 2 leader.

Those analysts believe al-Qaduli would have been expected to take control of the day-to-day running of ISIS, also called ISIL, if its leader, Abu Bakr al-Baghdadi, was killed or incapacitated.

The U.S. operation was intended to capture him alive, a U.S. official told CNN. Helicopters loaded with special operations forces swooped in on a vehicle carrying al-Qaduli, but at the last moment something happened that caused them to decide to fire on the vehicle instead. The official would not say what it was that caused them to modify the plan.

Defense Secretary Ash Carter announced the death at a news conference Friday morning.

"We are systematically eliminating ISIL's cabinet," Carter said, adding it was "the second senior ISIL leader we've successfully targeted this month."

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