If you talked to the FBI, or some other federal law enforcement officer, and they want to use that statement against you at trial, your lawyer will likely try to have that statement suppressed.
Winning a suppression motion for a confession in federal court is never easy - but here's the basic law that applies and some things to think about when you think about whether the statement that the federal agents took from you was against the law.
The Basic Rule
The basic rule about interrogation is that the government can’t force anyone to confess to anything. It comes from the same rule (the Fifth Amendment to the Constitution). A federal judge can’t make you testify at your trial. The AUSA can't make you talk to her in her office. The FBI can't make you talk when they show up at your house at 7:00 a.m. (and, for whether you should talk to law enforcement
, please see this page).
The point of this rule is that no person should ever have to choose between damning themselves by admitting to a crime, committing a different crime by lying to the court or federal law enforcement, or being held in contempt for refusing to say anything. The choice would be jail, jail, or jail – and the Constitution says that’s not fair, so you shouldn’t be forced to talk in the first place.
Police always make you feel like you have no choice about answering their questions, but there are only certain situations where the court will agree with you that it was not ok. Specifically, the conversation has to be both incriminating and forced.
Cops can ask you how tall you are, or what the capitol of Nebraska is (Lincoln), and neither of those answers are going to be bad facts for the government to use against you in court (unless it's some very sophisticated geography fraud). They are not incriminating, so the Fifth Amendment allows them.
This also means that they can ask you to say things that incriminate other people, which can be a pretty uncomfortable situation. Remember though, that if you helped someone else commit a crime you might be considered an “accessory” so statements about that would be incriminating for you, too. There are serious penalties for lying to federal law enforcement, but no penalties for refusing to talk to them. So, well, think about whether you want to talk to the feds
Because it has to be incriminating, the government can also force you to talk if they promise not to prosecute you. It has to be a real promise, though, so don’t just believe a police officer who says he will “go easy” on you if you cooperate (they ALL say that). A real binding promise will be written in an agreement letter, and will explain that you have “immunity” for what you are about to tell them. This page explains how immunity works in federal criminal cases
The court will assume that anyone who’s been arrested physically by the police felt forced to answer their questions. So, if you're under arrest, the police have to give you a Miranda warning.
Federal law enforcement can try to get around this by asking you questions when you’re not really in their custody yet. When a Customs agent knocks on your door at 6 in the morning and starts questioning you, even though it may not feel like it, you are totally free to say nothing and close the door. In that situation, in the eyes of the law, you aren’t being forced to talk, because you aren’t physically stuck there.
There are a ton of things cops do to make you feel like you have to answer their questions, but there are a few things that the court will look at to decide whether it was really a forced “custodial” situation – for example, handcuffing you, pointing weapons at you, telling you that you are under arrest or that you can’t leave, keeping you in a locked interrogation room, etc. The judge will look at all of the circumstances to decide whether a reasonable person in your position would have thought he or she was basically under arrest.
A confession is not forced if you just start talking, without being asked any questions. The law only protects you from unfair interrogations - not unfair blurts.
The easiest way for cops to prove to the court that you weren’t forced, is to warn you at the beginning that you don’t have to talk to them. Once they’ve warned you that you don’t have to talk, then unless there's evidence that you shouldn't have believed what them when they said you didn't have to talk, the court will assume that anything you tell them was voluntary.
Fighting it in court
If you confessed something to the police, and you felt like you had no choice at the time, then your lawyer can file a “Motion to Suppress” during the early stages of your case. The goal of this Motion is to convince the judge that the agents broke the law to make you talk to them, so what you said should not be used against you.
If you win the motion, the prosecutor has to decide whether they want to drop the charges entirely, or go to trial without telling the jury about the statement you made.