All criminal defendants are considered innocent until proven guilty beyond a reasonable doubt, and it is the prosecutor's job to meet this burden of proof. The first step in any case is the police investigation. Once the police have amassed the requisite evidence against an offender, they go to the local district attorney's office. The deputy or assistant district attorney assigned to the case makes the decision whether to charge the defendant, and what to charge him with. In some cases that might be easy -- in the case of a man who broke a window in a Radio Shack and was caught carting off electronics, the charge might be simply be burglary. However, take the example of a man caught standing over the dead body of his wife, with blood on his hands. If he deliberately hit her over the head, he is guilty of murder. If he pushed her violently and she hit her head, he may be guilty of manslaughter. If he was simply talking to her and she slipped and hit her head, he may not be guilty of anything. It is the prosecutor's job to review the evidence, decide what happened and what the charge should be. "You do have a lot of responsibility," says one assistant district attorney, "though sometimes your bosses are the ones deciding where to go with a particular case."

After the charge is filed, the prosecutor works with the police, the evidence and the witnesses to put together a compelling case. They may review the police reports as well as the accused's previous criminal records. A prosecutor might have to present his initial case to the grand jury. This is not a trial -- it is merely a forum for the prosecution. to present the case before a grand jury who will decide whether there is sufficient basis to proceed to trial, in which case the grand jury issues an indictment. This is the first hoop a prosecuting attorney must prepare to jump through.

In addition to these duties and knowledge of both the penal code and rules of criminal procedure, the prosecutor must have a strong grasp of the unspoken rules of his criminal court system. Is the judge assigned to the case prone to be lenient towards defendants? Does he require a particular format for his briefs? Is his court clerk helpful or intimidating? Will the trial start on time? These are questions that a good attorney must be able to answer. "Part of my job is knowing one judge from another and being friendly with their clerks and their staff," says one assistant district attorney. "It's not even about the law sometimes, just strategy. You need to be good with people. And good with chaotic situations." And with his huge caseload, a county prosecutor cannot afford to get bogged down with red tape.

Most criminal cases never make it to trial. The prosecutor will meet with the defendant's attorney to work out a plea bargain, in which the defendant pleads guilty to a lesser charge in exchange for a more lenient sentence. A seasoned prosecutor might meet the same legal aid lawyer or private criminal attorney many times in his career and will probably know what to expect from him.

If the case does indeed go to trial, the prosecutor's time will probably be consumed by preparations. A trial is not a minor event and a good attorney will spend hundreds of hours preparing for a trial, focusing on details down to the very last letter of his closing statement. Trials are not won on grandiose gestures in the courtroom, but on how well prepared, thorough and detail-oriented the attorney is. In many serious felony cases, the prosecuting attorney has been known to eat and sleep at work and his social life can stop completely. After all, it's not just the defendant's life that's on the line -- the attorney is also trying to find justice for the victim. "When I'm busy, it's ridiculous," says one prosecutor. "Everything stops but the case. You need to be able to give that kind of dedication to a trial without losing your mind. If you can't, then this is not the job for you."

The prosecutor's job is extremely demanding and heavy on responsibility. There is considerable burnout in the offices of big-city district attorneys. Not only is the work complex and often exhausting, but the prosecutor must also deal daily with the bureaucracy of the criminal justice system. Moreover, there are many tough ethical decisions to be made along the way. Public defenders are often asked how they could defend a murderer or a rapist: What if a guilty man goes free? But the prosecutor faces a similar dilemma: What if an innocent man is imprisoned? Sometimes the evidence points in one direction but, as we see often in the news, the real offender gets away. Could you live with the knowledge that out of your hundred cases, at least one defendant may be innocent and in prison for a crime he didn't commit?

Lawyers might find other aspects of a prosecutor's job troubling. How would you feel about accepting a plea bargain from a man who beat an old woman to death? What if he had information on a violent drug dealer that the police have been trying to catch for years? What will you tell the victim's family when the defendant serves 6 to 12 years for manslaughter rather than the 25 to life he would get for murder? "I do a lot more pleas that I thought I would," says one assistant district attorney. "I knew most of my cases would plead out, but it's still hard to do day after day." The vast majority of cases do settle. It may not seem just, but without plea bargains an already overloaded system would grind to a halt.

Yet, working as a state prosecutor can be an incredibly satisfying experience. You will be in court almost immediately and get trial and litigation experience your law firm colleagues will envy. The level of responsibility is high, and you will often have the satisfaction of putting away genuine bad guys and finding justice for victims who have been harmed.

An assistant prosecuting attorney has a large caseload and, while the hours are not quite as brutal as those of a corporate litigator, they can be quite demanding. A first-year prosecutor might also have a varied schedule, including overnight shifts. Starting salaries depend on the city. The starting salary for assistant district attorneys in New York is in the mid $40,000s; in most states it ranges between $25,000 and $40,000. Salary increases are usually determined by the department's budget. Prosecutors with years of experience can stay with the prosecutor's office, head a particular bureau or department, move into private practice or even become judges. Although it is possible to become an assistant district attorney right out of law school, most offices look for some prior litigation experience. Candidates go through a rigorous interview process as well as drug testing, written exams and background checks. You must also be a U.S. citizen and make a commitment to the office for a period of time, generally two to four years.