Prosecutor Links Slaying to Vehicle : Trial: In his opening statement, the attorney says defendant Mark Scott Thornton needed Kellie O’Sullivan’s car keys to flee the area.

Mark Scott Thornton kidnaped Kellie O’Sullivan at random and forced the Westlake nurse to his secret mountain hide-out before fatally shooting her--all so he could steal her car keys, a prosecutor said Tuesday.

Urging a Superior Court jury to convict the 20-year-old defendant of first-degree murder, Deputy Dist. Atty. Peter D. Kossoris said Thornton needed O’Sullivan’s vehicle to flee the area because local police had a warrant out for his arrest.

In his opening statement, Deputy Public Defender Howard J. Asher would neither deny nor confirm that his client murdered O’Sullivan. But Asher said the prosecution theory of the case is all wrong.

Asher acknowledged Thornton was under intense pressure to leave the area because the young man had violated his probation and faced a warrant for his arrest. Still, he said, prosecutors have no evidence to prove Thornton planned a murder.

If the jury finds Thornton guilty of first-degree murder and rules that he planned the act, he could be sentenced to death in the gas chamber. The prosecution expects to call at least 15 witnesses in the next three weeks to build its case.

But, Asher told the jury, “There will be no (death) penalty trial in this case.”

Thornton’s trial comes more than a year after O’Sullivan was killed Sept. 14, 1993. She had been missing for 12 days when two members of a search party, who had joined a massive hunt for her body, discovered it amid some thick brush in the Santa Monica Mountains.

Prosecutors charged Thornton with murder, kidnaping and robbery, saying he took the woman to the mountains and shot her. Thornton was arrested in Reno five days after O’Sullivan disappeared, and police say he had her truck with him.

Kossoris--weaving a long, tragic story in his opening statement--said the crime grew out of Thornton’s desire to leave the area quickly and avoid arrest for a juvenile probation violation, an offense that could have earned him no more than 60 days in juvenile jail.

Rather than face the short jail stay, Thornton embarked on a desperate path starting with forged checks and stolen credit cards and ending in murder and kidnaping, Kossoris told the jury. His path crossed O’Sullivan’s outside a Thousand Oaks pet store, where she had gone to buy bird seed for her parrot.

Kellie O’Sullivan got off work in the San Fernando Valley about 12:30 p.m. the day of her murder.

After going to a Calabasas bank and a computer store, she stopped to chat with a doctor friend with whom she ran marathons.

Her only other errand before the pet store was a stop at the cleaner on Thousand Oaks Boulevard, Kossoris said. That was a little before 2 p.m.

She was in a good mood in the pet store, Kossoris said. But her smile was gone sometime after 2 p.m., when Margaret Spaulding saw O’Sullivan and Thornton in the victim’s Ford Explorer.

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Spaulding is expected to testify that Thornton was in the driver’s seat and O’Sullivan, with her head hanging down, in the passenger seat. “The woman appeared to reach for something, and the man backhanded her against the passenger window,” Kossoris said.

Spaulding has said the vehicle was heading toward the Santa Monica Mountains.

Long before that day, Thornton had considered the Santa Monica Mountains the perfect place to dump a body, Kossoris said. In fact, he had told an ex-girlfriend from Glendale the year before just that.

Driving through the mountains after a school dance, Thornton turned to the girl and said, “I could take you someplace where nobody would ever find you,” the prosecutor said.

That was in October, 1992. Four months later, Thornton and another friend began hanging out at a place in the mountains only 7/10ths of a mile from where searchers eventually would discover O’Sullivan’s body, the prosecutor told the jury.

Thornton moved with his mother and stepfather to Ventura County in 1992. He had been on probation in Los Angeles County for a burglary, but that too was transferred to his new county.

At Thousand Oaks High School, he hung around with Darren DeWaele, a boy two grade levels below Thornton, according to DeWaele, who testified Tuesday.

Kossoris said that on July 10, the two boys broke into a Thousand Oaks storage facility. Testifying under a grant of immunity, DeWaele said that Thornton stole a handgun, some bullets and a $100 bill during that break-in on Thousand Oaks Boulevard.

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But that was not the only trouble for Thornton, Kossoris said. He also missed a meeting five days after the break-in with his new probation officer. What’s more, Thornton had been thrown out of his family’s house for some unstated reason and was living out of a room at an Econo Lodge motel, Kossoris said.

It was at the motel that he met Stephanie Campbell, who had just moved to Ventura County after her father changed jobs and was staying at the motel temporarily with her family.

Campbell and Thornton quickly became a couple, he said, but they broke up after agreeing that Thornton was not right for the 16-year-old girl.

By then, Thornton had more to worry about than a failed relationship, Kossoris told the jury. Probation officials had issued a warrant for his arrest on Aug. 31.

Thornton left the motel then and rented a room from a local Thousand Oaks couple, the prosecutor said.

Within two weeks, his new landlords discovered their checks missing. Kossoris said Thornton bought a police radio, maps and ammunition for the handgun he had stolen from the storage facility. He also put in a call to DeWaele, Kossoris said.

The two met at school the next day--Sept. 13--and went to several branches of the Home Savings of America bank, where they forged some checks for cash, Kossoris said. The next day, Thornton planned to steal a car and leave the county, the prosecutor said.

And, he said, Thornton wanted to take Stephanie Campbell with him.

After killing O’Sullivan, Thornton got a tattoo emblazoned on his body, Kossoris said. It read: “Stephanie.”

He also took that time to buy some camping gear and other items. That night, after Stephanie’s mother picked her up at work, Thornton was waiting for them at their house, Kossoris said.

“As Stephanie approached the front door, the defendant ran around the corner with a gun in hand and approached her,” Kossoris said. “He said, ‘Come with me, I have a gun.’ ”

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As he forced Stephanie into the stolen Explorer, Thornton fired a shot at the girl’s mother, Linda Campbell, Kossoris said.

Eventually, Stephanie persuaded Thornton to drive to Reno so they could go to the Circus Circus Hotel and Casino, the prosecutor said.

At Circus Circus, Stephanie managed to slip away from Thornton and alert the hotel’s security. While the guard plotted his strategy, Thornton was paging Stephanie.

Police surrounded him while he played a video game. After briefly pointing his gun at officers, Thornton surrendered. Kossoris said a ballistics expert was able to match the bullets taken from Thornton’s gun to those that killed O’Sullivan.

“We will urge you to find the murder is murder of first degree,” Kossoris told the jury, wrapping up his lengthy presentation that included maps, charts and graphs. “And we will also urge you to conclude that the murder is premeditated.”

The defense’s opening statement was considerably shorter than the prosecution’s.

Asher denied that Thornton had planned any murder. He said that his client had used stolen checks to purchase a pager, a large aquarium and a large television in the week before the killing.

“These are not the type of items you buy if you plan to commit a murder and flee police,” he said.

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Asher acknowledged that his client purchased bullets the day before O’Sullivan was killed. He insisted, however, that the ammunition was not bought “with a plan to kill anyone but to protect himself on the road,” Asher said, noting his client was carrying with him the money he had gotten from the forged checks.

Asher said his client realized he needed to leave town only after his landlord, Lenore Brier, discovered her checks had been stolen. “Mark spent a sleepless night on Sept. 13, unable to go back to the Briers and (with) nowhere else to turn,” Asher said.

Asher also denied a prosecution suggestion that Thornton “forced” O’Sullivan into her truck. Had that happened, he said, employees in the pet store would have noticed because O’Sullivan had parked out front.

In addition, Asher said the defense planned to attack the credibility of several key prosecution witnesses, including Spaulding, the woman who said she saw Thornton and O’Sullivan in the Explorer together.

In at least six separate interviews with police and prosecutors, he said, she has told different stories, once even saying she saw the victim and the defendant at 4:30--an hour after O’Sullivan was reportedly killed.

Asher said the coroner in Los Angeles who performed the autopsy on O’Sullivan’s body, Dr. James Ribe, also is not credible. “Dr. Ribe is willing to testify to whatever theory he is asked to support,” Asher contended.

And Asher said that Stephanie Campbell, another prosecution witness, was never kidnaped.

“Stephanie was not held by force and was free to leave at any time,” said Asher. “When was the last time you heard of a kidnaper paging his kidnap victim?”