1. Police notice: Generally speaking, the police will notify the criminal suspect or relevant parties after filing a case, which can be by summons, arrest, service of notice, etc.
2. Legal procedures: Criminal filing usually leads to a series of legal procedures, such as investigation, trial and hearing. In these procedures, the parties may get the information that they have filed a case.
3. Lawyers or legal representatives: If the parties have hired lawyers or other legal representatives, they can receive relevant notices or information to inform the parties.
4. Media reports: Some major cases or cases of public concern may be reported by the media, and the parties may learn about them through the media.