Via SFist, a line of riot police square off against sign-wielding protesters: Paste this image in your site, Myspace, Facebook, Ebay copy this code...

<a href="http://www.weeklybits.com/johannes-mehserle-guilty-of-involuntary-manslaughter-in-bart-shooting_article_11_74091.html"><img src="http://scienceblogs.com/tfk/images/grantpoliceprotesters.jpg" border="0" alt="Via SFist, a line of riot police square off against sign-wielding protesters en Tech WeBlogs WEEKLYBITS.COM"></a>

Within a week of the shooting, Mehserle had resigned (just before he was scheduled to be interviewed by the BART police internal affairs unit), and it wasn't long before he was charged with murder. Given the tensions in the community, the case was moved to Los Angeles.

On the stand, Mehserle insisted he had been reaching for his Taser, and his defense team pressed police department witnesses to show that officers were not well-trained in the use of their Tasers, and that it was not unreasonable for Mehserle to have mistaken his pistol grip for the Taser.

The prosecution pointed out that Mehserle's reaction to other officers right after the shooting was to attempt to justify using his gun by claiming he thought Grant was reaching for a gun, not simply insisting that he thought he was using his Taser. This is problematic, since 1) Grant's arm was being held securely by another officer, 2) Mehserle didn't act like he was trained to do if he felt like a gun was being drawn (he loosened his hold and stood up, which would allow an armed suspect to roll over and shoot) 3) Mehserle didn't act the way an officer is trained to act after intentionally firing a gun in self defense (they are trained to fire more than once, then to keep the gun drawn, while Mehserle fired once then quickly holstered the gun).

The East Bay Express summarizes the jury's options thus:

we thought it would be helpful to compare the four possible verdicts (five, if you include a hung jury) against the reported evidence so far:

1. Second-degree murder. To reach this verdict, the jury would have to conclude that Mehserle, after attempting to subdue Oscar Grant, stood up, purposely pulled out his gun, and shot the unarmed Grant in the back as he lay face down on the ground.

To reach this verdict, the jury would have to disregard Mehserle?s statements to fellow BART cops after the shooting that he thought Grant was reaching for a gun. But this verdict is bolstered by the fact that cops are trained to not stand up and let go of a suspect who they think is arming himself. The reason is that the suspect might roll over and shoot the cop.

But to reach this verdict, the jury would have to disregard Mehserle?s testimony in the trial that he meant to use his Taser on Grant, but mistakenly pulled out his gun instead.

2. Voluntary manslaughter. To reach this verdict, jurors would have to conclude that Mehserle killed Grant in the ?heat of passion? or because he unreasonably thought that Grant posed a threat to his life. That is, the jury would have to accept the testimony from several BART cops that Mehserle said after the shooting that he thought Grant was reaching for a gun, when, in fact, Grant had no gun.

In other words, [that] Mehserle thought Grant posed a threat, when he actually didn?t. The jury also would have to conclude that Mehserle?s belief was unreasonable. This conclusion is substantiated by video of the shooting, showing then-BART cop Anthony Pirone with his knee on Grant?s back, holding Grant?s arm ? the one that Mehserle said he thought was going for a gun. In short, Mehserle could not have reasonably thought that Grant was reaching for a gun when he couldn?t have physically done so.

This verdict also is bolstered by the fact that the BART cops who testified that Mehserle said he thought Grant was going for a gun were called to the stand by the prosecution. But to reach this verdict, jurors would have to disregard Mehserle?s later contention at trial that he meant to use his Taser.

3. Involuntary manslaughter. To reach this verdict, jurors would have to conclude that Mehserle meant to reach for his Taser, but instead grabbed his gun and then recklessly killed Grant. This verdict is bolstered by Mehserle?s own testimony.

But it requires that jurors disregard his repeated statements after the shooting that he thought Grant was reaching for a gun. The reason is that police officers are trained to use a gun ? not a Taser ? on a suspect armed with a deadly weapon. Officers are trained to use lethal force when faced with lethal force.

However, this verdict, often viewed as a compromise decision in homicide cases, may be preferable for jurors who believe Mehserle killed Grant by accident but don?t want to vote not guilty, or for those who believe that Mehserle meant to kill Grant but are reluctant to convict a cop of a more serious crime.

4. Not Guilty. This verdict requires jurors to conclude that Mehserle meant to pull out his Taser but accidentally grabbed his gun instead and that such an accident was reasonable under the circumstances. This conclusion is bolstered by testimony that BART gave officers only cursory Taser training. But it requires that jurors disregard testimony by fellow BART officers that Mehserle thought Grant was going for a gun.

5. Mistrial. This occurs when jurors can?t agree on any of the above verdicts and are said to be "hung." This result is not uncommon in police-officer-involved shootings, where there is evidence that a crime occurred but some jurors just don?t want send a cop to prison. This verdict also likely would take some time to reach, because judges routinely tell juries to keep deliberating until they come to a unanimous conclusion, as required under the law.

After the verdict, protesters gathered to object to a verdict that looks rather lenient. The Grant family expressed their disappointment at the verdict, but urged the protesters to remain nonviolent. Stores near likely protest sites boarded up their windows or filled them with posters expressing solidarity with Oscar Grant, hoping to divert any violence.

And, alas, some violence did occur. SFist reports a Foot Locker, a Whole Foods, and a jewelry store being "looted," though details are scarce. Police (Oakland PD, not Mehserle's former colleagues in the BART PD) were out early to keep any violence from spreading (as in the image above), and there are reports that protesters did direct some of their anger ? as well as bottles and rocks, unfortunately ? at the officers.

But things seemed relatively calm for much of the afternoon and evening. That's as it should be. The Chronicle adds an observation that "Many of the most aggressive demonstrators smashing the windows of banks and shops were white.? Oakland Police Chief Anthony Batts said the people causing trouble did not seem to be Oakland residents bent on voicing displeasure at the Mehserle verdict. He described them as outsiders 'who are almost professional people who go into crowds like this and cause problems.'"

We'll know more as this unfolds, but it matches my sense of things on the ground. Oakland doesn't want violence, it wants justice. Two Januaries ago, local businesses were damaged in riots, and there was a clear message from the community that such violence was not OK. It wouldn't surprise me in the least to learn that the violence was led by folks from outside who had hoped there would be rioting, and who instigated it on their own when it became clear that the community was handling matters nonviolently.