Judge Allows Use of Thornton Jail Visit Remarks : Trial: Prosecution will be able to play taped conversation between grandmother and suspect charged in Westlake nurse’s death.

Prosecutors may use incriminating statements made by Mark Scott Thornton during a jailhouse visit with his grandmother in their effort to convict the Thousand Oaks man of kidnaping and killing a Westlake nurse, a judge ruled Monday.

Ventura County Superior Court Judge Charles R. McGrath denied a defense motion that sought to keep jurors from hearing the conversation taped last year between Thornton and his grandmother, Lois Thornton.

McGrath’s ruling struck another blow to Thornton’s defense team, which has lost a series of pretrial motions filed before jury selection begins Monday.

“We’re disappointed that (McGrath) overruled our motion,” Deputy Public Defender Howard J. Asher said outside the courtroom Monday. He said Thornton “was subjected to improper police tactics, (with investigators) using his grandmother to try to extract certain statements.”

Prosecutors declined to disclose details of the conversation between Thornton and his grandmother.

The district attorney’s office alleges that Thornton, 20, kidnaped Westlake nurse Kellie O’Sullivan last September, stole her car, shot her to death and dumped her body in a remote area of the Santa Monica Mountains.

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He is also accused of kidnaping his former girlfriend and shooting at the girl’s mother, then fleeing with the 16-year-old to Reno, Nev., where he was arrested days later inside a casino.

Deputy Dist. Atty. Peter D. Kossoris argued Monday that there is ample case history that allows investigators to record conversations between inmates and relatives, then use those tapes at trial.

“I don’t see how anyone can consider Lois Thornton a government agent,” Kossoris told McGrath. “She didn’t get anything that was of benefit to her.”

Defense attorneys had argued that Lois Thornton was manipulated by sheriff’s detectives into getting her grandson to incriminate himself.

“We’re claiming there’s been a constitutional privilege that’s been violated,” argued Deputy Public Defender Susan Olson, one of Thornton’s two defense attorneys.

In other decisions Monday, McGrath denied a defense request to disallow evidence seized from Thornton’s Thousand Oaks home days after the kidnapings.

McGrath ruled that Detective Dennis Reed and his partner had sufficient cause to enter and search the room without a warrant, in part because the suspect was on probation for a prior conviction for breaking into a car.

Prosecutors on Monday declined to discuss what evidence was seized inside the room Thornton rented in the 1800 block of Marview Drive. But they disclosed that Thornton wrote a suicide note two months before he was arrested for murder, and has a history of mental instability.

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Asher argued that early discussions between Thornton and police should not be allowed at trial because of “significant ambiguity” about whether his client waived his right not to speak to investigators.

The defense attorney said Thornton agreed only to answer certain questions, and refused to discuss more detailed aspects of the kidnapings of O’Sullivan and his former girlfriend.

But McGrath disagreed, ruling before prosecutors could respond that Thornton fully understood his right not to speak to police. “I feel his waiver was free and voluntary,” McGrath said.

Last week, the judge refused to remove some misdemeanor theft charges from Thornton’s murder prosecution, and also decided to allow jurors to see graphic photographs of the O’Sullivan crime scene.

The trial is expected to last more than two months.

If Thornton is convicted, the penalty phase of the trial--in which jurors would decide whether he should be put to death or spend life in prison--could stretch into February.

McGrath has yet to rule on whether a prosecution witness named “Erika” can testify, if there is a sentencing phase of the trial, that Thornton committed sexual improprieties against her and once threatened her safety.