KSAT 12 / Reuters
FBI agents join local law enforcement at the scene
Apple Devil Kelley wounded 20 others at the First Baptist Church (19459012)
The FBI said his handset had been sent to his central crime lab, in Virginia, as local police could not unlock it.
Apple said it had "immediately" offered to help.
If Kelley had saved his (and) (19459015)
Dead man's finger
"It actually highlights an issue that you ' ve all heard about before, the advance of the technology and the phones and the encryptions, "said FBI special agent Christopher Combs.
"Law enforcement, whether at the state or local or the federal level, is increasingly not able to get into these phones."
However, there has been speculated that Kelley's phone.
Apple iPhones locked with a fingerprint ask for a passcode only after they have not been unlocked for a 48-hour period.
And it is because of the dead man's finger in the hours after his death, provided it had not run out of battery, or been deliberately switched off or rebooted.
