Judge Robert Perry denied the defense’s motion to permit peace officers to serve on the jury and granted most of the prosecution’s requests to limit the scope of expert testimony by two witnesses who are expected to be critical to the defense’s case.

However, he approved the use by the defense of a prior incident involving Grant resisting arrest in 2006 as evidence of his character and prohibited the use of Mehserle’s refusal to speak to BART police investigators regarding the shooting as evidence of a guilty mind.

The defense asked to include evidence of Grant resisting arrest during a traffic stop in San Leandro in order to establish a “character trait” for resisting arrest.

In one of a few impassioned exchanges in the nearly five-hour hearing at the Clara Shortridge Foltz Criminal Justice Center in Downtown Los Angeles, prosecutor David Stein argued against its inclusion, saying that resisting arrest is a habit, not a character trait, which would require more examples of Grant resisting arrest to establish.

The judge’s decision to allow the prior incident upset Grant’s family.

Cephus Johnson, Oscar Grant’s uncle, said in an impromptu press conference outside the courthouse that if anything, it was Mehserle who had a character trait for violence, pointing out that Mehserle was implicated in another alleged police brutality incident.

By far the lengthiest discussion of the day was on proposed testimony by two expert witnesses expected to be at the heart of Mehserle’s defense.

Defense attorney Michael Rains had asked for retired police captain Greg Meyer to be allowed to provide testimony saying that Mehserle’s hand motions as seen on video showed that he had intended to pull his Taser.

The judge mostly sided with a prosecution motion arguing that the jury should be allowed to decide this for itself, instead permitting only testimony that the hand motions would be consistent with a Taser draw.

The defense also asked for William Lewinski, a professor at Minnesota State University, Mankato who studies use of force in stressful situations, to be allowed to provide testimony postulating that “inattentional blindness,” in which an individual subject to a stressful situation suffers from tunnel vision, might have caused Mehserle to fail to notice that he had drawn his gun, not his Taser.

However, the judge ruled that, unless Mehserle himself provides evidence that he was suffering from the condition, it would be purely speculative to draw a link between inattentional blindness and the shooting.

Judge Perry also rejected a motion by the prosecution to allow police officers from serving on the jury. State law prohibits police officers from serving on juries, but Rains had argued that this prohibition would violate Mehserle’s 6th Amendment right to a trial by a jury of his peers.

Prosecution attempts to introduce Mehserle’s refusal to give a statement to BART Police investigators after the shooting, and use a breath alcohol test form as evidence the shooting was intentional, were denied on self-incrimination grounds.

Perry spoke at the beginning of the hearing to the modest crowd, saying that “everyone agrees that what happened [...] was a tragedy” and appealing for respect for the court rules from the gallery.

“This is not a sporting event,” Perry remarked, while approving a ban on buttons, T-shirts, and other articles of clothing advocating for one side or the other.

Johnson, who wore a “Justice for Oscar Grant” T-shirt to today’s hearing, said he would respect the rule when it comes into effect at the start of jury selection.

A final pre-trial hearing will be held Tuesday, June 1 in Los Angeles. Jury selection will begin the next day, with opening arguments expected approximately a week after that.

California Beat reporters Steven Luo and James Keith reported from Los Angeles. Contact Steven at sluo@californiabeat.org.

This story is part of our coverage of the Johannes Mehserle trial in Los Angeles, a public service journalism project for the Bay Area in partnership with the California Beat online news website.