Someone knew the crime happened and reported it to the police otherwise there could be no arrest warrant issued.
If something is unknown it is not known by someone or something.
the first to do something.
she, he, them, they, him, it, that, the group
Voyage into the Unknown happened in 1984.
Unknown Horizons happened in 2008.
Unknown Armies happened in 1998.
happened to me too... "Waiting-remaining time unknown" I just stopped trying...
Mission to the Unknown happened on 1965-10-09.
What happened to Padme's parents is still unknown
he got arrested 30 times!
Unknown...While reports say that her and her follow castmates were arrested for disorderly conduct, many say it was merely a publicity stunt.
Anything which is native to the place in which it is. Alien is something or someone who isnot native to that environment. It could also mean 'unknown', someone might say "that's alien to me".