An expert witness Wednesday disputed a defense forensic pathologist's surprise opinion that actress Lana Clarkson could have exhaled blood onto Phil Spector's jacket with her dying breaths after being shot through the spine.

Dr. John Andrews was called by the prosecution to challenge the theory sprung last week by renowned forensic expert Dr. Michael Baden that Clarkson could have breathed for three or four minutes after she was shot.

"I don't believe she could have been breathing," said Andrews, a Los Angeles County deputy medical examiner and a specialist in neuropathology.

Spector, 67, is accused of murdering Clarkson on Feb. 3, 2003, a few hours after she went home with him from her job as a nightclub hostess. The defense maintains that Clarkson was depressed and shot herself through the mouth, and used its forensic experts to explain how the blood could have gotten on the music producer's jacket if he didn't shoot her.

The prosecution contends the tiny bits of spattered blood on the jacket show Spector was within two or three feet of Clarkson, 40, when the trigger was pulled.

Andrews' appearance on the witness stand was perhaps the last round of a battle of scientific experts that has consumed much of the five-month trial. After his testimony, Deputy District Attorney Alan Jackson rested the prosecution's rebuttal case, and the defense began its rebuttal.

On cross-examination, defense attorney Christopher Plourd immediately attacked Andrews' qualifications, noting he was first certified as a forensic pathologist in 1999, although he had done decades of work in neuropathology as a researcher, clinician and professor in Utah.

The witness acknowledged that he was not as experienced an expert as Baden or other scientists called to the stand by the defense. But he noted that he had written widely in his field and is the editor of a new book on forensic pathology which deals with the work of several of the defense experts. He was present for part of Clarkson's autopsy, he said, as was Baden.

He disagreed with Baden's testimony that Clarkson's legs could have moved after she was shot through the mouth.

"Once her spine was transected, all spontaneous movement would have ceased," Andrews said.

Clarkson was found slumped in a chair, her legs extended. Defense lawyers say the reason there was no blood on her legs is because she was sitting upright and her legs extended after she was shot. Prosecutors say there wasn't blood on her legs because Spector was standing close by and holding a gun in her mouth.

Andrews acknowledged that he watched Baden's testimony and that he considered his theory that Clarkson's spine was not completely transected immediately but was further damaged on the way to the morgue.

"When Dr. Baden made that suggestion, it was an innovative thought," Andrews said. "When someone of Dr. Baden's stature suggests that I have to take it into consideration."

Commenting that "as scientists we have to try to prove ourselves wrong," he said he did further research and concluded that Clarkson suffered immediate "spinal shock," which would have prevented any reflex movements of the body. He also offered alternate theories of how her lungs became filled with blood.

He also disagreed with one opinion offered by his own colleague, Dr. Louis Pena, who said that Clarkson might have taken one or two shallow breaths after she was shot.

"I would disagree with that," he said of the idea that blood was inhaled in postmortem breaths. Andrews said there were other explanations for the blood in her lungs, including the pull of gravity as Clarkson's body sat upright for several hours before it was moved to the coroner's office for an autopsy.

As the defense began calling final witnesses, the judge said testimony would probably slide over to Monday. The final defense effort, known as surrebuttal, is designed to answer issues raised by the prosecution in rebuttal.

The defense called Tanara Henson, who saw Clarkson at a party a month before she died and said her demeanor changed from happy at the start of the evening to distressed later on.

The testimony was aimed at confirming that Clarkson was at the party and may have had a disappointing encounter with movie director Michael Bay. Bay testified for the prosecution, saying he did not remember seeing Clarkson there but didn't ignore her.

More of Clarkson's friends were due to return to the stand on Thursday.