The three main players in a criminal case are the prosecution, the defendant and the defense attorney.
The prosecution is the lawyer, or lawyers, representing the state and who is charged with resolving a criminal case. This happens primarily by one of two ways; either through a negotiated plea bargain, or by proving the defendant guilty of the charged crime to a judge or jury.
The defendant is the person accused of a crime.
The defense attorney is the lawyer who represents the defendant and will attempt to either negotiate a plea bargain or if the case goes to trial, the defense attorney will attempt to convince the judge or jury that the prosecution is unable to prove its case against the defendant.