How do assassin's get a car?

if the criminal is truly worthy of being called an assassin the plates wouldnt turn up anything directly useful

I can imagine myself as an assassin not necessary using stolen plates in the traditional sense rather those plates in your story would come back to someone who simply hadnt been seen by anyone for a long time - someone who as it turns out wasnt missed when he was quietly killed and disposed of several months ago

An assassin can buy a car like everyone else. If they're that great at their job, they wouldn't have to worry about be caught. Besides, they can use a false name while their on duty as an assassin.

You can't spell assassins!

,Use false platea legal car's details,onto similar car,in the area.

It's easy,just copy the number.

They'd probably steal one well in advance, switch the plates, possibly respray it to change the colour and stash it in a lock-up until they needed it.

Bought or rented it under a false name or jut sole it.

Always stolen.