We have been wondering if a dead body or missing limb could be used to unlock a phone.

The truth is that the issue is not a new one as it has been asked since at least the release of Apple's Touch ID. And yet, despite the years of coverage, no one has been able to agree on an answer.

So can smartphones make a distinction between the living and the dead, or not? The answer matters. If the fingers, eyes, or face of a deceased victim be used either by law enforcement or criminals to unlock a smartphone, then biometric locks have a brutally defined shelf-life.

This, of course, would stand in contrast to a strong alphanumeric password which can't (at least yet) be pried from your ever-so-quickly decaying body, and would suggest yet another reason that the security conscious should avoid biometrics like a privacy-violating plague.

Source: http://techguide247.com/2017/11/15/can-dead-body-unlock-iphone/