This is from
https://aoisora2525.com/kyotoanimation_20190719/ which unfortunately doesn't provide sources for every claim:
- On the day of the attack, a film crew from NHK was scheduled to visit KyoAni's studio to do some filming for a documentary. NHK wrote about their film crew having an appointment with KyoAni in the first revision of one their articles on the fire, but silently edited that fact out a few hours later:
http://archive.fo/LWelh
http://archive.fo/zaqIU
- NHK told KyoAni to relax security that morning so the film crew could go in and out unhindered. That's why the perp was able to simply go in and out of the unlocked front door.
- KyoAni's most renowned directors were all present in studio 1 that day because NHK said they wanted to do interviews with them.
-The NHK crew actually was very close nearby when it happened, after the perpetrator ran out he was filmed by the crew's director from his car.
- Supposedly KyoAni had locked the emergency exit on the rooftop roughly a week before because they had received complaints that some employees were throwing down cigarette butts from the rooftop.
