
Unknown caller.
It's got to be them.
The Big Bang Theory Season 12, Episode 23

But he wasn’t so anonymous, so UNKNOWN.
Money Heist Season 1, Episode 8

somewhere UNKNOWN.
And most likely...
Money Heist Season 3, Episode 2

takes a bullet to the face
from a person or persons UNKNOWN.
Breaking Bad Season 4, Episode 7

SUSPECT'S WHEREABOUTS UNKNOWN
Money Heist Season 1, Episode 1