When a person has been accused of a crime, and they're arrested by the police, they're read their "Miranda Rights." It's explained to them that they have the right to be silent, and if they speak, it could be detrimental to their case. If they keep quiet, no words can't be used against them in a court of law. Next, they're told they have the right to an attorney who will help them build a case that will offer the best solution, when all is said and criminal defence done. An attorney will be appointed to handle their case, if they can't afford one. Many criminal defense attorneys help others by taking on "pro bono" cases free of charge. Each attorney does his/her part to help those who don't have money to hire a lawyer on their own.
If the arrested person makes statements without first having the rights read to him/her, the statements will be thrown out of court. An attorney talks to his client and listens to exactly what happened. He knows that his job is to show that his client is innocent of all charges filed against him/her. This can be accomplished in various ways, since his client is innocent until proven guilty by the prosecution. Regardless of the type of case it is, the criminal lawyer will expect his client to tell the truth, since truth is the best way to defend anyone. He knows the prosecution attorney will see his client's situation in a different light, try to turn the truth around to benefit his case, and use his own legal strategy in court.
There are many strategies each attorney will use in court, but the prosecution must prove beyond a shadow of a doubt that the client committed a crime. If the case is a murder case, there are many types of defenses the lawyer may feel are best. Many people kill because someone was chasing them or broke into their home to harm them, which means self defense would be in the client's best interest. Some are found to be temporarily insane or intoxicated to the point of not realizing what they were doing at the time. In court, it's actually the two attorneys battling it out with each other, one defending his client, and defence attorney one working to make certain he/she is found guilty.
Clients do not speak nor defend themselves; that is left to the attorney. If there is no evidence to substantiate a crime, and the person charged has told the truth, he/she may be found innocent. A defense attorney will decide which path, and which defense strategy he/she will take to obtain the best verdict he can for his client