[dmix]

The iPhone in question was his (government) work phone and they already found a bunch of their other 'burner' phones in a trash bin, which they got access to. I find it unlikely he used his work phone for planning when they purposefully ditched other devices. Additionally, I doubt he knew the iPhone encryption would block investigators from accessing the data, so the fact they can't access it is most likely just coincidental that the device's battery was dead.

But this is just speculation...

I'm definitely in the camp that believes this is a legal stunt by the FBI to set a precedent using a highly publicized terrorism case which the public will support. A previous All Writs Act claim in 2014 by the FBI for a credit card fraud case involving an encrypted iPhone didn't change Apple's position on the matter, so they are trying again with a higher stakes case.

[asgfoi]

Yes I agree. I can't be a coincidence. They deliberately picked the best weapon in this debate, biased public opinion.