I am using email-to-case which works really well, however, I want to filter the cases coming from list of spam senders(email) to go in a spam queue and those cases which are not will go to non spam queue. The trigger works for manually created cases, but from cases from email, it does not work. The owner becomes the Default case owner set in support settings. How can I override the case owner into the queue when email-to-case if the owner becomes the default case owner?
You can follow this step, hopefully it will work.
You can find that, in the Email-to-Case setting Case Origin in set as 'Email'.
So, you could create assignment rule and add relevant condition along with the Case origin to route to a proper queue. There will be single assignment rule to be active, but it can have multiple conditions to route to a queue.