Will iPhone Face ID (and Android Face Unlock) work if you are dead?

They need your eyes open, and a normal view of your face.. And any disfigurement from violent death would keep it from working. But otherwise, works as well as chopping off your thumb to use for touch access.

No. The phone is not unlocked by the image of your face, but by the heat signature.

Exactly right @filmfann. It needs a heat signature and your face in a normal way. However finger print ID will work if the body is fresh.

Dead heads can be warmed artificially.

@Zaku You would have to recreate the heat signature, which is different than just warming a head.

@filmfann Do different people have signature head warmth patterns? Does it have trouble recognizing people when they’ve got a fever?

Yes, or when you wake up in the morning.

Maybe.