You won't be kept in the dark if criminal charges are filed against you, but it's easy to get lost in the complex maze of criminal procedure. Most criminal cases begin with a criminal complaint or grand jury indictment. In either circumstance, you will be served with, or at least sent, a notice of the charges.
Arrest and Booking
If your criminal case begins with an arrest, you'll be taken to the police station, booked and taken before the judge, usually within 24 hours. At the hearing, the judge may set bail or other terms for your temporary release and you are told when to return for the next hearing. Meanwhile, the police will investigate the circumstances leading to the arrest and provide information to the prosecutor.
Complaint or Indictment
The decision to file criminal charges is made by the prosecutor. If she decides to proceed, she either files a direct complaint against you in criminal court or takes the case to a grand jury to get an indictment. In either case, you are personally handed official notice of the charges and a summons, ordering you to appear in court on a particular date.
Threats Don't Always Materialize
If someone threatens to file criminal charges against you, all it means is that he will go to the police station and give a report. The police may or may not investigate. If they do investigate and find enough evidence to proceed, they give the file to the prosecutor who may or may not decide to file charges. If so, you are personally handed a complaint or indictment and a summons to appear. You may also be taken into custody.