The Criminal Complaint Or Information
Criminal cases begin with either a criminal complaint or information. A criminal complaint or information is the initial pleading document that the prosecutor files with the court against a defendant that alleges criminal conduct.
Many people have the mistaken belief that the alleged victim can either "press charges" or "drop charges" against a defendant once the police have investigated a matter. As soon as the investigating authority (typically the police department) completes their investigation, they refer the evidence they have gathered to the prosecuting agency. When the information is received by the prosecuting agency, the prosecuting agency (usually the district attorney's office or the city attorney's office) solely has the authority to evaluate the evidence and determine whether to prosecute, decline to prosecute, or request additional information from the police department, for any potential criminal case.
In summary, the police will arrest and "book" a person into a detention facility, alleging that the defendant engaged in some type of criminal conduct. However, it is the prosecutor, and the prosecutor only, who has the authority to review evidence presented to them and determine whether sufficient evidence has been presented, to allege in the complaint or information a crime, and to prosecute the case.
The alleged victim of criminal activity cannot "press" or "drop" charges pending against a defendant. Please keep in mind, though, that the alleged victim's input into the case, through the prosecuting agency, can impact the prosecutor's decisions as the case proceeds. The victim's input into the case can ultimately affect how a prosecutor prepares for and tries the case, or how the prosecutor negotiates a resolution through the plea bargaining process.