Police officers have killed over 700 people so far this year. But while officers employ lethal force on a very regular basis, they are almost never held accountable for their actions. In 2014 FiveThirtyEight reported the following:

"A recent study out of Bowling Green State University — reported by The Wall Street Journal — identified 664 incidents from 2005 to 2011 in which police officers were arrested for having 'pulled, pointed, held, or fired a gun and/or threatened someone with a gun.' These incidents resulted in 98 deaths."

FiveThirtyEight continues:

"Of the 71 arrests for murder and nonnegligent manslaughter, just 31 came when officers were on duty. That’s about four a year during the study period."

We saw this in the cases of Mike Brown and Eric Garner. After grand juries for the respective cases “failed to indict,” the officers who killed Brown and Garner each escaped trial and were absolved of legal culpability.

This may be why California governor Jerry Brown just banned the use of grand juries for cases in which cops kill civilians. A similar law is being pushed in New York. But what effect will bans like this have on the oft criticized way we deal with police brutality in America? To answer this question, we need to understand more about what grand juries are, when they’re used, and how they work. For help, we turned again to criminal defense attorney and legal expert John Hamasaki. This interview has been edited for length and clarity.

ATTN: In the last month, around the anniversaries of the deaths of Eric Garner and Mike Brown, there have been some renewed discussions around the use of grand juries in cases of police killings. We keep hearing that the grand jury “failed to indict” or “refused to indict” the police officers responsible for the deaths of Mike Brown and Eric Garner. Can you explain what that means?

John Hamasaki: I think that the language that has been used in the media coverage of the non-indictments has been extremely problematic. There’s an old saying, interestingly enough coined by the former chief judge of New York state, that a prosecutor can get a grand jury to "indict a ham sandwich." Meaning, that essentially, due to the degree of control of the prosecutor, a grand jury will do whatever the prosecutor says to do, whatever the prosecutor wants. Once a case goes to grand jury, the outcome is almost always guaranteed to be the desired outcome of the prosecutor.

So when the media reports it as the grand jury failing to indict the police officers or the grand jury refusing to indict the police officers, that is placing the blame, the responsibility, on the wrong party—on the grand jury, instead of the prosecutor who presented the case to the grand jury in the first place. A grand jury is just made up of ordinary citizens tasked with doing their civic duty, they aren’t lawyers trained in the criminal justice system. They are alone in a room with a prosecutor who is responsible for training them on the law, explaining the facts and presenting evidence.

A grand jury generally does whatever the prosecutor wants. And if a prosecutor doesn’t want the grand jury to return an indictment, it won’t. If a prosecutor doesn’t want a police officer to be held responsible for killing one of us, that officer is not going to get indicted by a grand jury. That officer is going to walk free.

ATTN: Is there a way to hold a prosecutor accountable?

JH: I think that is where the video in the Eric Garner case has been so powerful. We all watched Eric Garner die. We watched him call out for help as [NYPD Officer] Pantaleo choked him to death. We all heard Eric Garner repeat “I can’t breathe” over and over as Officer Pantaleo and the NYPD took his life.

ATTN: And, we heard the media report this as a failure of the grand jury to indict the officer. Can you tell me why criminal cases go to grand juries in the first place? Is that the normal procedure?

JH: While there are differences between some states, generally speaking, once law enforcement has conducted an investigation into a potential criminal matter, the investigation is presented to a prosecutor for a charging decision. The prosecutor then has the option of filing a criminal complaint or going through the grand jury process.

If the prosecution goes by way of criminal complaint, the prosecution files a document listing the charges the defendant is facing. In a felony case, the defendant is then entitled to a preliminary hearing. A preliminary hearing is an open adversarial process overseen by a judicial officer. This means that the courtroom is open to the public, anyone can come in and observe the hearing, including the media. The prosecutor is responsible for presenting the state’s case against the charged individual. The defendant is present and is entitled to certain rights, including cross-examination and the ability to call their own witnesses. The process is overseen by a judicial officer who can rule on whether certain evidence should be admitted or not. At the end of the proceeding, the judge determines whether or not there is sufficient evidence for the matter to go to trial.

A grand jury, on the other hand, is convened in secret by a prosecutor. It is closed to the public and it is generally just the prosecutor alone in a room with the grand jurors. There is usually not a judge to oversee the proceeding and the defendant has no right to be present, call witnesses or even be aware that it is taking place. It’s not just hidden from the public, the media can’t be present to provide an account, the families of the victim and defendant are barred from viewing the proceeding. Everything about it is done in secret, behind closed doors.

And at the end of it, when the grand jury doesn’t return an indictment, the transcript is usually sealed. And no one knows what went on with the grand jurors alone in that room with a prosecutor. And in the case of Eric Garner, who we all watched Officer Pantaleo choke to death, we don’t know how this could happen. How could a grand jury not hold the killer responsible? The crime was completely caught on video. What went on behind closed doors that could change what we all saw with our own eyes?

ATTN: I think maybe people don’t quite understand. How can a prosecutor really influence a grand jury? The evidence is the evidence, right?

JH: We might know at least part of the answer if they would allow the transcripts to be unsealed. But they are fighting tooth and nail against the release of the transcripts. I would think, if they felt they conducted a fair hearing, why not release the transcripts and silence the critics, allow oversight, restore some degree of faith in the justice system?

Releasing the transcripts is an obvious step, but even that won’t make up for the fact that this was a secret proceeding, hidden from the public and the media. Because it’s not just the words that are used, it’s how they are said, what emphasis is placed on which words and as seemingly minor things as gestures and facial expressions. For example, say the prosecutor was questioning Officer Pantaleo, what tone did he use? Was it accusatory, or was it comforting and understanding?

Did the prosecutor instruct the police officers to come dressed in uniform with their shoes polished and their badges visible in order to try and artificially boost their credibility? In what manner did the prosecutor address those with evidence against Officer Pantaleo? Was he dismissive or fair? The thing is, even if the transcripts are released, we will never know what really happened behind the closed doors of a grand jury. And that is the power and the purpose of grand juries. To keep things hidden from us.

ATTN: Why would prosecutors shield police? If it is their job to prosecute, why would they treat police any differently?

JH: I don’t think folks realize how closely police and prosecutors work together on a daily basis. They are both part of the same system of law enforcement, they are often work in the same building. They eat together, drink together. They are co-workers and each side is dependent on the other. The police investigate crimes and bring the evidence to the prosecutor. The prosecutor then brings a criminal case with that evidence and uses the police as witnesses at trial.

If they aren’t working closely together or cooperating each side can make the other side suffer. The police can do shoddy investigation, fail to secure evidence and refuse to investigate criminal activity if they feel they are being disrespected by the prosecution. The prosecution can choose not to prosecute cases involving police or cases important to police. That is why resisting arrests and assaults on officers are almost always prosecuted. Each side protects one another.

Also, state prosecutors are generally elected and have to be concerned about the police union actively campaigning against them. No prosecutor wants the local police union calling them “soft on crime.”

ATTN: California just eliminated the use of grand juries to probe cases of police killing civilians. How will cases involving cops proceed now?

JH: The bill that just passed and was just signed by the governor, SB227— eliminating the use of grand juries in the cases of police killings—I think it’s a great step. But someone asked yesterday, while everybody was celebrating, “Well, how often has California used grand juries in cases of police killings?” And I couldn’t think of a single example.

ATTN: So is the bill just symbolic?

JH: It’s not necessarily just symbolic, it may be preventative, meaning that at least it will prevent prosecutors from using grand juries to obstruct justice by shielding police from the justice system in the future.

But after the passing of this legislation, I did a little research about California and police killings. There’s been over 400 people killed by police in California in the two and half years from January 2013 to July of this year—400 people. And I’m not aware if police have been charged in any of those cases. The only recent prominent cases that I can think of are Oscar Grant, who was shot by an officer while face down and handcuffed, and Kelly Thomas, the mentally ill man was brutally beaten to death by police—but these were both in 2011. Both of those cases were charged by complaint and went through preliminary hearing, and both judges found sufficient cause to hold the officers over for trial.

So the problem in California hasn’t necessarily been the use of the grand jury by prosecutors to shield police who kill. The problem is that California police and prosecutors don’t even get to the stage of a charging decision.

And the police simply shouldn’t police themselves. The idea that somebody’s going to do a really probing, searching, in-depth investigation of their coworker just isn’t realistic. It may happen, but looking at it from the outside, people investigating themselves doesn’t build confidence that it’s a fair procedure.

The other reform that’s been suggested is to have an outside independent prosecutor review all police killings. There are generally other state prosecutors that are able to come in but don’t have those same relationships with the local cops as local prosecutors. This would allow there to be at least some degree of confidence that an outside prosecutor has reviewed the case. Obviously, there are still some problems with that, but I think it at least gets rid of that— the inherent conflict of investigating one's coworkers.

But getting rid of grand juries in police cases is a good first step. Let’s not celebrate too soon though, we still have a long way to go before we can start to restore some degree of confidence that police who kill will face justice in our criminal justice system.