Thornton Defense Attorneys Face the Ultimate Courtroom Test : Law: The two public defenders are in a battle to determine whether killer will be sentenced to die.

Susan Olson and Howard Asher had represented murderers before. But never had someone’s life depended on how well they argued a case.

Then they were assigned to defend Mark Scott Thornton--taking on the county’s most experienced death penalty prosecutor in a battle that will determine whether the 20-year-old Thousand Oaks man eventually faces execution for the murder of Westlake nurse Kellie O’Sullivan.

In recent weeks, that battle has turned on whether jurors in the death penalty phase of Thornton’s murder trial will ultimately be swayed by a defense that has worked overtime to portray Thornton as a victim.

The two public defenders--graduates of the Ventura College of Law--have devoted four weeks of testimony to accounts by 46 doctors, educators, Thornton family members and others describing the pitiful childhood of the central figure in the county’s most publicized murder case in years.

They are not minimizing the tragic death of Kellie O’Sullivan, they say. But they are trying to explain the reasons behind it.

“We are seeking an understanding of Mark Thornton, not an acceptance of his actions,” Olson said.

Whether the defense strategy works or not, the case put together by Olson and Asher is being called one of the most compelling, exhaustive death penalty defenses ever presented in a local courtroom.

And the two longtime public defenders who devised it are receiving widespread praise.

“I don’t think anyone has ever done a better job in any of the capital cases I’ve tried,” said Thornton prosecutor Peter D. Kossoris, who is trying his sixth death penalty trial.

Others who have watched the case closely agree.

“If I had an opportunity to trade the so-called dream team in Los Angeles for this team, I wouldn’t do it,” said the county’s top public defender, Kenneth I. Clayman.

Olson and Asher have been trying some of the most serious cases for the public defender’s office for years in Ventura County. But each time they received a potential death penalty case, the district attorney’s office had decided against seeking the maximum punishment.

With the Thornton arrest, that changed.

From the beginning, the two lawyers wanted to learn as much about their client as quickly as possible. And then, they wanted to give that information to the jury.

Along the way, they tried every legal maneuver available to them.

Before the trial, Olson and Asher tried unsuccessfully to get the charges dropped by attacking the grand jury process, saying Latinos were underrepresented on the panel and that prosecutors had too much say in how the group was selected.

“This is a case of someone’s life,” Olson said. “You need to bring forward every issue that has some merit.”

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After the trial started, the defense lawyers did not come out directly and admit that their client was the killer. Instead, they tried to pick apart the prosecution theory in hopes the jury would find Thornton not guilty of the so-called special circumstance required for a death sentence.

During closing arguments, however, they finally conceded he was the killer.

Some prosecutors fault Olson, the lead attorney for the defense, for such a strategy--saying she should have saved the county two months of trial time by simply admitting Thornton’s guilt and proceeding straight to the penalty phase of his trial.

“She is the ideological public defender, someone who thinks everyone who commits a crime ought to go free,” Senior Deputy Dist. Atty. Richard E. Holmes said.

But Clayman said a public defender’s job is to aggressively protect a suspect’s interests. He said Olson’s strengths lie in her “enormous credibility in the system, tremendous respect from the bench.”

Asher is “the ultimate trial lawyer,” Clayman added, describing Asher as an attorney who has no fear about taking on a high-profile case.

In their long battle to save Thornton’s life, the two attorneys have developed some emotional involvement with the outcome of the case--and with Thornton himself.

They say they truly believe that the reason for Thornton’s crime lies somewhere between the strain put on him by his dysfunctional family and a mental deficiency with which they say he has been diagnosed.

Thornton kidnaped O’Sullivan in Thousand Oaks in September, 1993, drove her to the Santa Monica Mountains at gunpoint and shot her once in the chest and twice in the stomach. Prosecutors say she was on her knees when she was killed.

Not disputing the basic facts of the case, the defense has tried to generate sympathy from the jury for Thornton during the evidence phase of the penalty trial.

In recent weeks, perhaps the most revealing testimony came from Markita Sarrazin, Thornton’s mother.

Under a blistering and at times rancorous direct examination by Olson, she admitted that she had failed her son as a mother. She said she had been a drug user for years and that her main interest in life was her womanizing husband.

The husband, Pierre Sarrazin, also testified that he had mistreated his stepson.

The jury gave no sign of how it was affected by the testimony, if at all. But Thornton did. On several occasions he broke down and wept.

Asher said he believes the defense has “portrayed a fairly accurate picture of him.”

“Not fairly accurate,” Olson quickly interjected. “Accurate.”

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Olson has lived in Ventura since she was 15, after her family moved from the Los Angeles area. Although she graduated from the Ventura College of Law in 1975, she never completed an undergraduate college program, dropping out of UCLA after one semester to get married.

She made it into law school by completing 60 credit units at Ventura College. Then, after being rejected initially by both the public defender’s and the district attorney’s offices, she was hired in 1975 by then-Public Defender Richard Erwin as “extra help.”

Olson and her second husband, optometrist Mike Jaurequi, have a 6-year-old son. The couple are avid rock climbers and have scaled Mt. Whitney, she said.

Much like O. J. Simpson prosecutor Marcia Clark, Olson said she finds it difficult balancing motherhood and a major court case. But she said her husband is very involved in helping with their son, so she can put in 70-hour workweeks when her job requires it.

Asher, who was born in Chicago and initially raised in the Pacific Northwest, came to the Los Angeles area with his family at age 10. He earned a history degree from the University of California, Santa Barbara in 1971 and worked as a teacher in Camarillo before becoming a public defender in 1982.

“I like the advocacy. I like the conflict. I like the underdog status,” said Asher, a marathon runner and amateur baseball player.

He has been married to Kathy, his high-school sweetheart, since age 19. They have two boys, ages 18 and 20, who both attend UC Santa Barbara.

In court, Asher usually assumes the role of the tough, hard-nosed questioner, while Olson displays more emotion in her arguments.

“Sue can be more subjective,” Asher said. “The other side of the coin is she is also more creative and imaginative and has the ability to bring life to other issues and explain things so that people can understand them.”

But during times when Thornton has cried, Olson is normally the one offering him a pat on the back or a tissue.

“I don’t think there’s any way you can defend someone for this long and not feel close to that person,” Olson said. “He’s young, he’s vulnerable and he’s scared.”

“He cries out for affection,” Asher added. “Mark is 20, and I have a 20-year-old and an 18-year-old. I get calls from all three of them.”