An amnesic secret service agent of Arab origin must recover his memory to clear his name and stop his terrorist brother from detonating a dirty bomb on US soil.

Both, the first one years ago forced him to make a choice.
The second one put him back to the same situation.

Which attack is the inciting incident?

Star Trek:Voyager has an episode on the very same subject you described. It is the episode 4.22 called "Unforgettable". If your memory were erased and you were put in the very same circumstances, would you fall in love again with the same person? It is a very moving bitter sweet love story.

Not really a logline, but a mini synopsis of my project.
After the death of their third brother in a drone attack, one brother joined the French service service, the other one a terrorist cell. When a failed attack that kills their remaining baby brother bring them together, both have to face the consequences of the choices that they made years ago. Will they betray each other or their cause?

My story is more about: are we shaped by the events that happen to us or are we shaping the events that happen to us? Do the events dictate our choices or do our choices dictate our future events?
Two brothers, two different destiny. Both shaped by the same failed drone attack, but both responded diametrically opposite way.