A prosecutor files criminal charges when four conditions line up: probable cause connects a specific person to a specific crime, the statute of limitations has not expired, the admissible evidence is strong enough to realistically win a conviction, and prosecuting the case serves the public interest. An arrest does not trigger charges on its own. The prosecutor makes an independent decision, weighing legal thresholds against practical judgment about how the case would actually play out in court.
Probable Cause Has to Connect the Suspect to the Crime
The first condition is probable cause, the Fourth Amendment standard that asks whether the known facts would lead a reasonable person to believe a crime was committed and the suspect was responsible. The Supreme Court has described it as resting on “the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.”1Constitution Annotated. Amdt4.5.3 Probable Cause Requirement
Think of it as the gap between “there is good reason to believe this person did it” and “we can prove it.” Both matter at different stages. Probable cause is the entry threshold. Proof beyond a reasonable doubt comes much later, at trial. To file charges, the prosecutor only needs enough credible information to justify formally accusing the person and moving them into the court system.
The Statute of Limitations Must Still Be Open
Even an airtight case cannot be charged if the deadline has passed. Every crime carries a statute of limitations — a cutoff after which prosecution is barred regardless of how strong the evidence is.
At the federal level, the default is five years from the date of the offense.2Office of the Law Revision Counsel. 18 USC 3282 – Offenses Not Capital Capital offenses, meaning crimes punishable by death, have no time limit at all, so an indictment can land decades after the conduct.3Office of the Law Revision Counsel. 18 USC 3281 – Capital Offenses Terrorism offenses also carry extended or eliminated deadlines. State windows vary widely. Murder almost universally has no deadline. Other felonies commonly run three to ten years, and misdemeanors often expire within one to three. Confirming the clock has not run is one of the first practical checks a prosecutor makes before investing in a case.
The Evidence Has to Be Admissible and Strong Enough to Convict
Probable cause and a live limitations period get a case in the door. They do not get a conviction. The prosecutor’s next question is whether each piece of evidence will survive the adversarial process and persuade a jury beyond a reasonable doubt.
Physical evidence like DNA, fingerprints, or a weapon gets examined for quality and chain of custody. A gap in how a sample was stored or transferred invites a contamination argument and a motion to exclude. Digital evidence — emails, texts, cell phone location data — is checked for authenticity and context. A text that looks damning on its own can read very differently inside the full thread.
Witness testimony draws some of the hardest scrutiny. A witness who had a poor vantage point, holds a grudge, or has given inconsistent accounts may be truthful and still fall apart on cross-examination. Jurors tend to read confidence and consistency as credibility, fair or not, and prosecutors know it.
Miranda and the Risk of a Suppressed Confession
Confessions carry their own filter. The Supreme Court has held that the prosecution cannot use statements obtained during custodial interrogation unless the suspect was first warned of the right to remain silent, that any statement can be used against them, and the right to an attorney.4Legal Information Institute. US Constitution Annotated – Exceptions to Miranda A confession taken without those warnings, or under conditions suggesting coercion, is almost certain to be thrown out. If the confession is the backbone of the case, suppression can end the prosecution before it begins.
The Exclusionary Rule and Illegally Obtained Evidence
One factor that quietly kills many cases is the exclusionary rule, which bars prosecutors from using evidence collected through unconstitutional searches or seizures. If police searched a home without a warrant or a valid exception, anything they found is inadmissible, and evidence discovered because of that illegal search may be tainted as well.
Prosecutors routinely decline to file charges when the core evidence was obtained improperly. Rather than lose a suppression motion in open court, they pass. This is also why prosecutors often work closely with investigators before an arrest, to make sure warrants and procedures will hold up.
Evidence That Helps the Defense Counts Too
Prosecutors are not just building a case for guilt. Under Brady v. Maryland, suppressing evidence favorable to the accused violates due process, whether the prosecutor acted in good faith or not, as long as the evidence is material to guilt or punishment.5Justia. Brady v. Maryland That shapes the charging decision directly. An alibi witness, a contradictory forensic report, or a recanting co-defendant has to be factored into whether a conviction is realistic. Department of Justice policy pushes federal prosecutors further, requiring them to present evidence that “directly negates the guilt of a subject of the investigation” to the grand jury before seeking an indictment.6United States Department of Justice. Justice Manual 9-5.000 – Issues Related to Discovery, Trials, and Other Proceedings
When all of this is weighed, experienced prosecutors evaluate the case as a defense lawyer would. Which witnesses can be impeached? What motions will be filed? Where will the defense find reasonable doubt? If the realistic answer is that a jury probably will not convict, charges often do not get filed, even when the technical probable cause threshold is met.
The Case Has to Be Worth Bringing
Evidence quality is not the whole picture. Prosecutors exercise discretion shaped by several considerations that have little to do with whether they could technically win.
Severity of the offense matters. A violent felony with a traumatized victim almost always gets charged if the evidence is workable, because the harm demands a response. A minor property crime with strong evidence may still be passed over if the societal harm does not justify the resources a prosecution consumes.
A suspect’s criminal history plays a role. Repeat offenders face charges more readily. A first-time offender involved in a nonviolent incident is more likely to be routed into a pretrial diversion program, an alternative that lets the person avoid a criminal record by completing supervision, community service, or treatment. Federal diversion is unavailable to people accused of offenses involving serious bodily injury, firearms, child exploitation, national security threats, or leadership roles in criminal organizations.7United States Department of Justice. Justice Manual 9-22.000 – Pretrial Diversion Program
Victim cooperation can be decisive. If the victim refuses to testify or actively opposes prosecution, the path to conviction narrows sharply. Domestic violence cases run into this constantly, and prosecutors have to decide whether other evidence can carry the case alone.
Federal policy also requires prosecutors to seek a sanction that is “sufficient, but not greater than necessary” and to conduct an individualized assessment of each case rather than reflexively pursuing the most severe available charge.8United States Department of Justice. General Department Policies Regarding Charging, Pleas, and Sentencing That policy is meant to curb charge-stacking, where counts are piled on primarily to pressure a plea rather than to reflect the actual conduct.
How the Decision Turns Into Formally Filed Charges
Once a prosecutor decides to go forward, the case enters the court system through one of a few paths depending on offense severity and jurisdiction.
Complaint or Information
For less serious offenses, usually misdemeanors, a prosecutor can file a charging document directly with the court. The document identifies the specific charges and lays out the factual basis for probable cause. Some jurisdictions also use a document called an “information” for felony charges, which works similarly but applies to more serious offenses that do not require a grand jury.
Grand Jury Indictment
Federal felonies take a different route. The Fifth Amendment requires that no person be held to answer for a capital or otherwise infamous crime without a grand jury indictment.9Constitution Annotated. Amdt5.2.2 Grand Jury Clause Doctrine and Practice Federal Rule of Criminal Procedure 7 reinforces that: any offense punishable by death or by more than one year in prison must be prosecuted by indictment.10Justia. Federal Rules of Criminal Procedure Rule 7 – The Indictment and the Information A grand jury of citizens hears the prosecutor’s evidence in a one-sided, closed proceeding and decides whether probable cause supports charging the suspect.
The federal grand jury requirement does not apply to the states. The Supreme Court held in Hurtado v. California that states are not bound by the Fifth Amendment’s grand jury clause.11Legal Information Institute. Hurtado v. People of the State of California Roughly half of states still use grand juries for serious felonies by choice or state constitutional requirement, while others rely on preliminary hearings or let prosecutors file an information.
Preliminary Hearing
When charges are filed by complaint rather than indictment, the defendant is entitled to a preliminary hearing, where a judge evaluates whether probable cause supports the charges. In federal cases, that hearing must happen within 14 days if the defendant is in custody, or 21 days if released.12Legal Information Institute. Federal Rules of Criminal Procedure Rule 5.1 – Preliminary Hearing Unlike a grand jury proceeding, the defense can cross-examine witnesses and challenge the evidence, and the hearing gives the defense an early chance to argue for dismissal.
When a Prosecutor Decides Not to Charge
Declining to prosecute is just as much an exercise of discretion as filing. Prosecutors pass on cases when the evidence is too thin, when resources are tight, when a diversion program is the better fit, or when prosecution simply would not serve justice in the specific situation.
Even after charges have been filed, a prosecutor can walk away by entering a nolle prosequi, a formal notice to the court that the prosecution is dropping the charges. That is not an acquittal. Because double jeopardy protections do not attach until trial begins, charges can theoretically be refiled later if new evidence surfaces.
Courts are deeply reluctant to override a decision not to charge. The charging power belongs to the executive branch, and forcing a prosecution raises separation-of-powers problems. In practice, if the prosecutor concludes a case is not worth pursuing, there is very little a victim or anyone else can do to compel a different result.