As long as the statute of limitations has not expired, they can refile the charges unless the charges were previously dismissed with prejudice. The warrant is the notification. Although it would be nice if the court would send out letters to people telling them that charges have been filed, there is no requirement to do so and with the exception of a few municipal courts, I know of no courts that do that.
It is possible that the charges were initially declined Due to lack of evidence that the police officer further investigated and represented the charges.
Answers to AVVO questions are for general purposes only and do not establish an attorney-client relationship. This answer is not a substitute for legal advice and should not be relied upon without a full consultation with an attorney that can fully look at issues involved.