SHUT YOUR MOUTH! REALLY, ZIP IT!
If you have been arrested in Missouri, you can be held for up to 24 hours in jail without any formal charges being filed against you. Frequently, the arresting officer, a detective or sheriff's deputy will try to question you while you are being held. Don't say anything to anyone, including other inmates. There are inmates who may try to lessen their own sentence by testifying against you.
You have a right to be silent - use it. Tell the officer you have a lawyer (even if you don't) or that you want to speak to a lawyer. They should stop attempting to question you at that point, but they may not. Just don't talk. The police can and will lie to you to try to get you to confess. And by the way, it is perfectly legal for the police to lie to you. I've had many clients confess when they were told (falsely) about witnesses to the crime, fingerprint evidence or the buddy they were with already told the whole story. Lot's of times it isn't true, but any statement you make to them can be used against you in court. If you go to trial, you can't be forced to testify. But...any statements you made that can't be kept out by your attorney will be heard by the jury. The best case is the one where the client says absolutely nothing.
The police will also tell you that it is better to tell truth. No, it's not. The truth can sometimes be very, very bad. These men and women have one agenda: to gather enough evidence to convict you.
If you've seen the show "The First 48", you will notice a distinct pattern with the detectives. Most of the time, they have little or no physical evidence or witnesses connecting the suspect to the murder. What do they rely on the most? Convincing the defendant to confess. I want to throw the remote through the TV when, after a few hours of questioning, the suspect admits to the crime. Guess who's going to jail? The guy who opened his mouth. Guess who's going home and back to his family? The guy who wisely shut his mouth.