Someone needs tell the Apple lawyer the 'customer' (terrorist) is DEAD.
Someone should tell the FBI and the prosecutors that the suspect and their defendant is DEAD. There is no case to prosecute and therefore the evidence has become moot. Search warrants are quashed in such events. There IS no investigation for any prosecution. The FBI is on a fishing expedition. There is no search warrant outstanding because they don't know what they are looking for. They admit it themselves and a search warrant must SPECIFY what they intend to find and what they intend to seize from their search. They don't know what is going to be on the iPhone. Ergo, they are fishing.
Apple has already responded to the actual search warrants for the terrorist's iCloud account contents. They complied because they were the custodians of the those data.
Apple is NOT the custodian of those data on the iPhone.
Just tonight as I was typing this, it was announced on NBC that Google, Microsoft, Twitter, and Facebook are all backing Apple on its stance.
Ironically, although they did not point out the irony, NBC followed with an example of WHY this is important with a hospital in Hollywood having to pay thousands of dollars because their computers were locked by hackers. . . and it was cheaper to pay the RANSOM to the criminals to unlock them than it was to have computer experts remove the ransomware that was keeping them from running for twelve days! It is this very scenario that is why Apple is loath to write backdoor software for this iPhone!