There are six primary steps in a criminal jury trial: jury selection, opening statements, presentment of the state or prosecutor's case, presentment of the defendant's case, closing arguments, and jury deliberations.
Jury Selection or Voir Dire
A criminal jury trial begins with jury selection, which is called voir dire (to tell the truth). A pool of potential jurors is gathered from voter/BMV registrations. Out of this pool an initial set potential jurors are randomly seated. Ohio requires 12 jurors for felony cases and 8 jurors for misdemeanor cases. Once the first set of potential jurors are seated in the jury box, the prosecutor and defense attorney take turns ask the potential jurors questions. The purpose of the questions is to gather background information and determine if a prospective juror has any bias or conflicts that would prohibit him/her from being on the jury. After the questioning, both the prosecutor and defense attorney seek to have those who cannot fairly sit as a juror excused. The judge makes the final decision as to whether or not a potential juror can fairly and impartially judge the case. As potential jurors are excused they are replaced by others from the initial pool and the process continues until there are no more objections to the seated potential jurors, who then become the actual jury.
Once the jury is selected, both sides (prosecution and defense) then give opening statements. An opening statement is intended to be an overview of what either side believes the evidence will be or show. Prosecutors tend to explain the nature of the charges against the defendant and how they believe that the evidence will support a finding of guilt. After the state gives its opening statement, the defense provides its perspective. In my opening statements I find it important to tell the jury my client's side of the story, one which sometimes has been untold until then.
Prosecution Presents Its Case/Witnesses
The primary and usually longest part of a criminal jury trial is the presentment of the state or prosecutor's case. This consists of calling witnesses. Witnesses provide testimony (I saw, I did, I heard, etc.) and some witnesses provide testimony and introduce evidence (I collected a DNA sample, I took this picture). Some testify about subsequent examinations or tests done on evidence (DNA, ballistics, etc). After each witness has answered the prosecutor's questions, the defense attorney is permitted the opportunity to question the state's witness. This process of questioning a state's witness by the defense attorney is called cross-examination; it is considered to be the hallmark function of a defense attorney at trial. The prosecutor will continue the process of calling witnesses who provide direct testimony and are then cross-examined until the prosecutor believes he has proven his case beyond a reasonable doubt or there are no more witnesses left to testify.
Defense May Present Witnesses
After the state has called all of its witnesses, the defense is permitted, but is not required, to call witnesses to the stand. In many trials the defense does not call any witnesses. This is because the defense has no burden of proof. In a criminal trial the state, and state alone, must convince the jurors of the defendant's guilt beyond a reasonable doubt. The defense does not need to prove innocence. Therefore, if the defense can create sufficient reasonable doubt about the defendant's guilt through cross examination, there is no need for defense witnesses.
Closing arguments are conducted once all the testimony and evidence has been given to the jury. The prosecutor and defense attorney use the closing arguments to convince the jurors to vote their way. Prosecutors argue/explain to the jury why their witnesses should be believed or why the physical evidence shows the defendant's guilt. The defense attorney explains why the evidence is lacking or witnesses were not credible, and therefore, the appropriate verdict is not guilty.
Jurors are finally permitted to begin to discuss and deliberate the case after closing arguments. The jury as a whole must determine for each charge or alleged crime whether the defendant should be found guilty or not guilty. In criminal cases a jury's verdict on each charge must be unanimous. This means that all 12 (or 8) jurors must vote the same - all 12 must vote guilty or all 12 must vote not guilty. If a unanimous vote cannot be reached, the case is declared a mistrial due to a hung jury and the whole process must be completed with a new jury pool.