There is a statement from us senator I am trying to find the source but he essentially says (after that briefing they gave 1-2 days ago) that iran has intel on our assets operating from gulf countries.I wouldn't jump to conclusions that it was a targeted assassination - that's a pretty tall building, the tallest in a cluster of tall buildings and the drone could have just hit it on the way to another target. The drones are reported to fly relatively low to avoid radar after all.
These drones usually fly low and hit low too, or on the ground so very odd to see hit it that high.
But fair fair.
IranianTV: Ali Larijani is expected to address the nation soon.