When they start deliberating, probably this afternoon, jurors in the trial of former BART police Officer Johannes Mehserle will have to weigh the arguments of a prosecutor and defense attorney who disagree on nearly every facet of the case save one - that Mehserle shot Oscar Grant in the back Jan. 1, 2009.

During closing arguments Thursday, jurors were told that the video-recorded killing during an arrest at BART's Fruitvale Station in Oakland was either an intentional act by a cop who "lost all control" or a tragic accident by an officer who intended to subdue a suspect with a Taser.

Either the 22-year-old Grant never resisted Mehserle before being shot or he fought him to the end. Either Mehserle has profited since from the lies of his colleagues in blue or he's been hounded by prosecutors under political pressure to deliver his scalp.

After 13 days of testimony, prosecutor David Stein and defense attorney Michael Rains put their clashing spins on the case, with Stein asking for what would be a historic verdict against an officer in a use-of-force case: second-degree murder, punishable by 15 years to life in prison.

"It can never be lawful to shoot an unarmed man," Stein said, "when that man is face-down in the process of putting his hands behind his back."

'Let's pack our bags'

Rains asked jurors to acquit Mehserle, 28, of murder as well as manslaughter, saying, "Let's pack our bags and go home."

When the court session ended Thursday, Rains was near the conclusion of his argument. Stein will deliver a rebuttal argument today before jurors are instructed on laws that apply to the case and then retreat into a meeting room.

There, they will be allowed to discuss the case with one another for the first time. Unless they can reach a verdict in a case involving dozens of witnesses, six videos and scores of documents in a few hours, they will continue deliberations Tuesday morning, after the holiday weekend.

Contrasting styles

About 50 people filled Judge Robert Perry's courtroom to hear the closing arguments by attorneys who differed in style as much as in substance.

Stein spoke slowly and evenly, mostly standing at a lectern following notes in a binder as he called up footage of the shooting played on two big-screen televisions.

Rains was more animated, shouting some of his points as he paced around or hunched over the lectern, scanning back and forth across the jury box.

The attorneys argued over whether Mehserle's actions fit not only the theories of second-degree murder, but also those of voluntary manslaughter and involuntary manslaughter.

Mehserle testified last week that he had decided to use his Taser on Grant while trying to handcuff him, and after thinking Grant was reaching in his pocket for a gun.

Prosecutor sees lies

On Thursday, Stein argued first, telling jurors that Mehserle was lying - both about his belief that Grant reached for a gun and about pulling his firearm by accident. Stein showed how the ex-officer's pistol holster was designed to prevent an assailant from snatching the weapon. A hood must be rolled forward and a lever depressed before the gun comes free.

After the shooting, Stein said, Mehserle never told fellow officers that he had meant to fire his Taser. He referred to testimony from another former BART officer, Anthony Pirone, who said Mehserle had walked up to him minutes after the shooting and said, "Hey Tony, I thought he was going for a gun."

"He was trying to justify it," Stein said. "He's saying, 'I meant to do what I did, but I have a justification.' "

Rains started his argument with a direct reference to the implications of the verdict. Some community leaders, activists and others believe the shooting underscored a larger problem of police officers abusing people of color with little accountability. Grant was black, and Mehserle is white.

East Bay tensions

The trial was moved to Los Angeles in part because of the tensions the killing caused in the East Bay. Rains told jurors their job was not to exact revenge, to redress social or racial injustices, or to make "some sort of commentary on the state of relations between the police and the community in this country."

Rains said Mehserle had a reputation as an unaggressive officer, while Grant had once fled from San Leandro cops after a traffic stop, forcing them to use a Taser on him.

If Mehserle had intended to shoot Grant, he would have fired his pistol more than once and then kept the gun out as he assessed the threat, Rains said. Instead, the defense attorney said, Mehserle looked shocked after firing his gun, said, "Oh s-, I shot him," and quickly put the weapon away.