Can police use the finger print of a dead person to unlock their phone?

The short answer to these question is, yes.  The dead have no privacy rights. Naked Security reports that corpses can’t assert privacy rights in courts.

The second reason is that other individuals who may have sent incriminating information to the deceased person’s phone have no claim to privacy rights over the information they have sent.

Forbes has published a report of what it says is the first known case of police using a dead man’s fingerprints in their efforts to get past the protection of Apple’s Touch ID authentication technology.

Can facial recognition be used in the same way? Marc Rogers, a security researcher with Cloudflare, tells Forbes that this liveness detection system “can be fooled simply using photos of open eyes.” 

That means cops should still be able to unlock a dead person’s iPhone X so long as they cover the cadaver’s closed eyes with photos of open ones, reports Find Biometrics.