Thornton Gets Death Penalty in Murder of Westlake Nurse : Courts: Judge will rule next month on whether to impose the jury’s recommendation. At 20, the Thousand Oaks man could become youngest convict on Death Row.

Deliberating just seven hours on one of the biggest murder cases in Ventura County history, a jury Monday condemned 20-year-old Mark Scott Thornton to death for abducting and shooting a Westlake nurse during a 1993 carjacking.

The Thousand Oaks man, who could become the youngest convict on California’s Death Row, stared straight ahead and displayed little emotion as Superior Court Judge Charles R. McGrath announced the verdict to a courtroom that overflowed with the curious.

McGrath will decide next month whether to impose the death penalty or reduce Thornton’s sentence to life in prison. The jury, after hearing testimony for four months, spent five hours Friday and two hours Monday morning deciding on the punishment.

“He got what was coming to him,” said juror Carlos Chacon of Simi Valley. “This guy was cold.”

Prosecutors and members of the victim’s family smiled broadly upon hearing the jury’s recommendation.

“It was the right verdict,” Deputy Dist. Atty. Michael K. Frawley said. “He doesn’t have a conscience. He doesn’t put any value on human life.”

Cliff O’Sullivan Sr., the victim’s former husband and father of their 6-year-old son, said the young boy wanted Thornton to receive the death sentence.

“My son’s opinion was that Thornton should be taken out to the woods and shot the same way Kellie was,” O’Sullivan added. “I agree with him, of course.”

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Thornton, who did not take the stand on his own behalf, demanded to be sentenced without delay, after the judge asked him if he would waive his right to a speedy sentencing hearing.

“No, I want to be sentenced as soon as possible,” Thornton said sternly.

As guards and defense attorneys escorted him from the courtroom, Thornton turned toward news photographers and waved goodby.

Outside court, jurors said they chose the death penalty for Thornton because of the aggravated circumstances of O’Sullivan’s kidnaping and shooting.

“I think about her daily . . . the brutality of her murder,” said juror Patricia Johnson of Oxnard. “It was just so coldblooded. I really don’t think about him anymore. I don’t want to hear his name. I don’t want to see his face.”

Neither Thornton’s mother nor stepfather appeared at the verdict hearing. His grandmother, Lois Thornton, came to the courtroom.

But as the room quickly filled with relatives of the victim and curious county workers, including Sheriff Larry Carpenter, the grandmother got up and left, without waiting to hear the verdict.

Defense attorneys, who argued that Thornton’s life should be spared, said they expected the jury to vote for life in prison without parole.

“I think it’s a shame that we have to kill a 19-year-old who has had to go through the things that Mark has,” said Deputy Public Defender Susan R. Olson, referring to his age at the time of the crime. “It’s very hard to comprehend.”

His attorneys argued that Thornton’s life was shaped by neurological problems and neglect by drug-abusing parents. They also argued he did not rank with society’s worst killers.

Still, O’Sullivan’s disappearance and death shook Thousand Oaks, a community known for its low crime rate. Hundreds of volunteers helped look for her during a 12-day land and air search.

O’Sullivan was on her way to pick up her son from day care on the afternoon of Sept. 14, 1993, when she disappeared. Court testimony later revealed that a gun-toting Thornton confronted her outside a Thousand Oaks pet store and forced O’Sullivan to drive off with him in her Ford Explorer.

Thornton, who was wanted at the time on a juvenile-probation arrest warrant, needed the truck to flee the area.

He drove her to a remote area of the mountains off Mulholland Highway and ordered her into an alcove, where he shot O’Sullivan once in the chest and twice in the back “for good measure,” prosecutors argued.

After getting a tattoo in Simi Valley, Thornton then kidnaped his estranged girlfriend, shot at her mother and headed for Northern California. He was arrested in Reno five days later.

Although he was driving the nurse’s truck, he denied ever seeing her, claiming to have found the vehicle complete with the keys.

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But a week after his arrest, two civilian searchers came across O’Sullivan’s decomposed body, still clad in her nurse’s uniform.

Jurors, who in December convicted Thornton of first-degree murder under special circumstances, said they identified with O’Sullivan because she was a hard worker and good parent who did nothing to contribute to her murder.

Several jurors embraced members of the victim’s family and prosecutors, offering words of comfort. Other jurors likened the victim to their own family.

Juror Chacon said: “My wife’s her age.”

Others, such as jury forewoman Tammy Wilson, related to O’Sullivan because she was a mother.

“I have a 5-year-old son and a 2-year-old daughter,” Wilson said.

Still, the defense thought it could offset O’Sullivan’s sympathetic qualities by demonstrating that Thornton is a slow learner who had lived a difficult life.

In her opening statements, Olson told the jury: “Mark Thornton was not born a 19-year-old with a gun in his hand.”

After the verdict, Olson maintained that Thornton does not deserve his sentence.

“We thought we presented a strong case for preserving his life,” said Olson, sounding exhausted and disappointed. “We put on a very complete history of the difficult life of this young man and the things he has had to face.”

Judge McGrath refused to allow prosecutors to put O’Sullivan’s family members on the witness stand during the penalty phase of the trial to tell the jury about the impact the death had on them.

Prosecutors said they thought that ruling might be their undoing.

“We were concerned,” acknowledged Frawley, “since we were unable to give them a full picture of her life.”

Even without such evidence, Deputy Dist. Atty. Peter D. Kossoris said Thornton deserved death because he committed a coldblooded act of murder.

Kossoris, however, expressed doubt whether Thornton would ever be executed, even if the judge upholds the verdict.

He said only two out of nearly 400 killers sentenced to death in California have been executed since capital punishment was reinstated in 1978. If the judge imposes the death sentence, Thornton will be sent to San Quentin prison in Marin County, where nine Ventura County murderers await the death penalty, according to the state Department of Corrections.

“It will be a while before we find out what will actually happen to him,” Kossoris said.

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Even so, family members who huddled outside the courtroom after the verdict said the jury did its job.

A tearful Dee Flanagan, O’Sullivan’s cousin, said it helps “knowing that the person who killed Kellie will be executed.”

Cliff O’Sullivan said he was going home to explain the verdict to his young son.

And then, O’Sullivan said, “We will put this to bed.”

Staff writers Miguel Bustillo, Carlos Lozano and Kenneth R. Weiss and correspondent Ira E. Stoll contributed to this story.

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A Look Back

Chronology of the Mark Scott Thornton case:

* Sept. 14, 1993: Westlake nurse Kellie O’Sullivan disappears. That night, 19-year-old Mark Scott Thornton abducts his former girlfriend and shoots at the girl’s mother.

* Sept. 19, 1993: Thornton is arrested in Reno, after the 16-year-old girlfriend tells a security guard she has been kidnaped. O’Sullivan’s truck is found in Thornton’s possession.

* Sept. 26, 1993: O’Sullivan’s body, with three gunshot wounds, is found in the Santa Monica Mountains.

* Dec. 19, 1994: A jury, after deliberating for less than five hours, convicts Thornton of first-degree murder with a special circumstance that qualifies him for the death penalty.

* March 20, 1995: A jury recommends that a judge sentence Thornton to death for the abduction and slaying, citing the aggravating circumstances and senselessness of the act.