LOS ANGELES (AP) — Prosecutors told a judge Tuesday that prison time would be the only appropriate punishment for a white former transit officer convicted in the 2009 videotaped shooting death of an unarmed black man on an Oakland train platform.

The severity of the crime by defendant Johannes Mehserle would make probation a disservice, Alameda County Deputy District Attorney David Stein added in his 20-page legal filing.

Stein didn’t specify the amount of prison time he was seeking when Mehserle is sentenced Nov. 5.

The “defendant not only took the life of an innocent person, but he also put the lives of others on the platform as well as those on the train at risk,” Stein wrote.

Mehserle’s attorney, Michael Rains, said in court documents that his client should be granted probation because he made “a tragic and irreversible error” while doing his job as a Bay Area Rapid Transit officer.

Mehserle, 28, was convicted in July of involuntary manslaughter in the death of 22-year-old Oscar Grant. Jurors also found a gun-use allegation to be true.

Involuntary manslaughter has a sentencing range of two to four years, while the gun allegation carries a term of three, four or 10 years.

Superior Court Judge Robert Perry will have several options in sentencing Mehserle that include tossing out the gun enhancement that was written into law to punish robbers and other armed criminals.

The shooting on New Year’s Day 2009 was videotaped by a handful of bystanders and prompted protests and rioting after Grant’s death and after the verdict.

The trial was moved from Alameda County to Los Angeles because of racial tension and extensive media coverage in the San Francisco Bay area.

Mehserle testified that he thought Grant had a weapon and decided to shock him with his stun gun but instead pulled his .40-caliber handgun. Grant was unarmed and face down when he was shot.

Rains also said during the trial that Mehserle told a colleague before the shooting: “Tony, Tony, Tony, I can’t get his hands. I’m going to Tase him.”

Stein, however, pointed out that Mehserle didn’t claim in the moments after the shooting that it was an accident.

“If the sentence in this case is to serve any purpose whatsoever, it must serve as punishment,” Stein wrote in his filing. “Punishment for the unlawful taking of a human life and for the attempt to cover up criminal conduct by testifying under oath that the shooting was the result of ‘taser confusion.’”

Prosecutors had sought a second-degree murder conviction, but jurors were given the choice of lesser charges including voluntary and involuntary manslaughter.

In reaching its decision, the jury found Mehserle didn’t mean to kill Grant, but his behavior was criminally negligent.

Rains noted in his filing that Mehserle didn’t have a criminal record prior to the shooting and wouldn’t pose a threat to the public if he was placed on probation.

Mehserle remained in custody as he awaited sentencing. Rains has filed a motion for a new trial that will be considered during the sentencing hearing.

Copyright 2010 The Associated Press.