Authority to interrogate suspects in a criminal case rests with sworn government investigators — local police and sheriff’s deputies, state agents, federal special agents, and military criminal investigators — along with grand juries, which can compel testimony under subpoena. Prosecutors supervise and question witnesses in formal settings but rarely interrogate suspects directly. Private security guards and store investigators are not in this category and cannot force you to answer. Whoever is asking the questions, the Fifth and Sixth Amendments set hard limits on how government interrogation can be conducted, and evidence obtained in violation of those limits can be excluded from trial.
Local Police and Sheriff’s Deputies
Most criminal interrogations in the United States are conducted by municipal police officers, detectives, and sheriff’s deputies. City departments cover crimes within their limits; sheriff’s offices cover unincorporated county areas. The detective working a robbery in a mid-sized city, not a federal agent, is the one who sits across the table in the interview room.
State Investigators
State police and state bureaus of investigation reach further. They take over when a crime crosses county lines, when a local department lacks the resources or expertise, or when a case involves statewide criminal networks. Homicides, multi-county drug operations, and organized crime often end up on a state investigator’s desk, and state agents also back up smaller local departments that have no dedicated detective unit.
Federal Agents
Federal agents question suspects when a crime violates federal law, crosses state borders, threatens national security, or occurs on federal property. Each agency has its own lane. The FBI handles terrorism, cybercrime, public corruption, and large-scale fraud as the primary domestic intelligence and law enforcement agency.1FBIJOBS. Special Agent Overview The DEA pursues narcotics organizations and seizes assets tied to the drug trade.2Drug Enforcement Administration. Special Agent The ATF covers firearms, explosives, arson, and tobacco and alcohol trafficking. The Secret Service handles counterfeiting and major financial fraud alongside its protective mission. Homeland Security Investigations targets cross-border crime including human trafficking and smuggling. Each can independently question suspects within its jurisdiction.
Military Criminal Investigators
The military runs its own criminal justice system under the Uniform Code of Military Justice, and each service branch has its own investigative agency.3Defense.gov. Uniform Code of Military Justice The Army’s Criminal Investigation Division handles serious offenses involving Army personnel. The Naval Criminal Investigative Service covers the Navy and Marine Corps and is staffed by civilian federal law enforcement officers inside the Department of Defense.4Naval Criminal Investigative Service. About NCIS The Air Force Office of Special Investigations covers the Air Force and Space Force.
Military interrogators work under a stricter disclosure rule than civilian police. Under Article 31 of the UCMJ, anyone subject to the code who wants to question a suspect must first explain the nature of the accusation, inform the suspect of the right to remain silent, and warn that any statement can be used at a court-martial. Unlike the civilian Miranda rule, Article 31 applies whenever a service member is questioned about a suspected offense, not only in custody. Statements obtained in violation of Article 31, or through coercion, are inadmissible at a court-martial.5Office of the Law Revision Counsel. 10 USC 831 – Art. 31 Compulsory Self-Incrimination Prohibited
Grand Juries and Prosecutors
A grand jury can do something no police officer can: compel you to answer. It can issue a subpoena requiring a witness to appear and testify, or to produce documents and other evidence. Refusing to comply without a legal basis can lead to civil or criminal contempt, including jail until the witness cooperates.6Congress.gov. Grand Jury and the Prosecutor
Prosecutors themselves usually don’t interrogate suspects the way detectives do. They guide investigations, present evidence to grand juries, and question witnesses in that formal setting. When a suspect already has a lawyer, professional conduct rules in most jurisdictions require the defense attorney’s consent before a prosecutor contacts the client, and in practice prosecutors have a law enforcement officer run the interview.
Private Security Is Not Law Enforcement
Private security guards, store loss-prevention staff, and corporate investigators do not have the legal authority of sworn officers. They cannot arrest you in the traditional sense and cannot compel you to answer. You are generally free to walk away from questioning by a private party.
The main exception is the shopkeeper’s privilege, recognized in most states, which lets a store employee briefly detain someone they reasonably suspect of shoplifting long enough to investigate and contact police. Some states extend limited detention authority to security officers at critical infrastructure sites. Even then, the detention must be brief and reasonable, and must be handed off to law enforcement once officers arrive. Because private security personnel are not government agents, Miranda does not apply to their questioning — a confession made to a store detective is not thrown out for lack of a warning. The constitutional rules below govern government interrogation.
Your Rights When a Government Officer Questions You
The Fifth Amendment protects every person from being “compelled in any criminal case to be a witness against himself.”7Congress.gov. Fifth Amendment In Miranda v. Arizona, the Supreme Court converted that principle into a procedural requirement: before any custodial interrogation, officers must tell you clearly that you have the right to remain silent, that anything you say can be used against you, that you have the right to a lawyer during questioning, and that one will be appointed if you can’t afford one.8Justia US Supreme Court. Miranda v Arizona, 384 US 436 (1966)
When Miranda Applies
Miranda warnings are required only during “custodial interrogation” — when you’ve been taken into custody or your freedom has been significantly restricted. Courts use an objective test: would a reasonable person in your situation feel free to leave? The officer’s private belief that you’re a suspect doesn’t count, and neither does your own sense of pressure. What matters is how much your freedom of movement was actually curtailed.9Congress.gov. Custodial Interrogation Standard
Several common situations fall outside the requirement. A routine traffic stop is not custodial unless freedom is restricted to a degree associated with a formal arrest. Being questioned at a police station is not automatically custodial if you went there voluntarily and are free to leave. Questioning in your own home usually isn’t custodial either, unless officers have placed you under arrest there. For juveniles, courts give weight to the detainee’s age in evaluating custody.
Invoking Your Rights
If you tell officers you want to remain silent, they must stop. If you ask for a lawyer, all interrogation must cease until counsel is present or you voluntarily reinitiate the conversation. The catch is that courts require the invocation to be clear and unequivocal. A hedged line like “maybe I should get a lawyer” may not be enough. Say it plainly: “I want a lawyer,” or “I am not answering any more questions.”
You can waive your Miranda rights and agree to talk, but the waiver must be voluntary, knowing, and intelligent. If you start talking and change your mind, you can invoke your rights at any point.
The Sixth Amendment Right to Counsel
A separate layer of protection activates once formal criminal proceedings begin, through an indictment, arraignment, or initial court appearance. From that point, the Sixth Amendment guarantees the right to have your attorney present during any interrogation related to the charged offense. The government cannot deliberately question you about those charges outside your lawyer’s presence, including through informants or undercover agents.10Legal Information Institute. Custodial Interrogation and Right to Counsel The right does not attach before charges are filed.
What Happens When These Rules Are Broken
The main consequence of a flawed interrogation is suppression. Under the exclusionary rule, courts throw out evidence obtained through unconstitutional methods, on the theory that removing the payoff is the most effective way to deter illegal conduct.11Congress.gov. Adoption of Exclusionary Rule A confession obtained during custodial interrogation without Miranda warnings is generally inadmissible at trial. Suppression isn’t automatic in every scenario, though. If you were warned, waived your rights, and then confessed, the statement comes in. Physical evidence found as a result of an un-Mirandized confession can often still be used, as long as the original confession wasn’t coerced through force or threats.
Coerced Confessions
A separate constitutional rule bars confessions that were involuntary — obtained through physical abuse, threats of illegal action, deprivation of food or water, or false promises of leniency. Courts look at the totality of the circumstances: how long the interrogation ran, the suspect’s physical and mental state, and whether the tactics were calculated to overcome free will. Officers are allowed to bluff about the strength of their evidence, but they cannot threaten actions they have no legal authority to take.
Suing an Officer
Under 42 U.S.C. § 1983, you can sue a state or local official who violates your constitutional rights while acting in an official capacity.12Office of the Law Revision Counsel. 42 US Code 1983 – Civil Action for Deprivation of Rights A claim requires showing the official was acting under government authority and deprived you of a right secured by the Constitution or federal law. Remedies include compensatory damages, punitive damages, and injunctive orders.
One significant limit: the Supreme Court held in 2022 that a Miranda violation on its own, where officers skipped the warnings but did not actually coerce the suspect, does not support a Section 1983 suit. A Miranda violation, the Court found, is not necessarily a Fifth Amendment violation and does not meet the threshold for a civil rights claim.13Supreme Court of the United States. Vega v Tekoh, No. 21-499 (2022) To sue, you generally need to show actual coercion, excessive force, or other conduct that independently violates the Constitution.