As Phil Spector sat in the courtroom, hands trembling, a forensic expert told the jury Thursday that actress Lana Clarkson was stronger than the record producer and could have shot him more easily than he could have shot her.

Dr. Vincent DiMaio, who has testified in Spector's murder trial that Clarkson committed suicide, also said she probably fired the gun in "a spontaneous reaction of some sort. Stupid. Based on alcohol."

The testimony drew an angry response from the prosecutor, who kept up a hostile, rapid-fire attack on the witness for more than two hours. He accused DiMaio of "cherrypicking" and "manipulating" facts. The witness accused the prosecutor of doing the same.

"Look at Mr. Spector," DiMaio said at one point, drawing jurors' attention to the frail, diminutive defendant. "He has Parkinson's features. He trembles."

The 67-year-old Spector is charged with murdering Clarkson within hours of meeting her. She was working as a hostess at the House of Blues and went home with him after closing time.

"She was 25 years younger, 7 to 9 inches taller," DiMaio said. "She outweighed him by 25 pounds and was in better health than he was. ... Her reflexes would have been greater. Her strength greater. It would be more likely for her to have shot him than for him to have shot her."

Deputy District Attorney Alan Jackson noted that the witness had said earlier that Clarkson, 40, had residual limitations from having broken both her wrists more than a year before her death.

"So you're manipulating the facts," Jackson said.

"No sir, you're manipulating what I said," the witness said. "I said when you consider all of these things together it's more likely for her to have killed him because of the physical disparity."

During the prosecutor's acerbic inquiry, DiMaio said his consideration of Clarkson's life story and her physical attributes had little to do with his conclusion that she shot herself in the mouth at Spector's mansion about 5 a.m. on Feb. 3, 2003. The scientific evidence that guided him was blood spatter, gunshot residue and the nature of Clarkson's wound in her mouth, he said.

The witness, a medical doctor with a specialty in forensics who has been chief medical examiner in Dallas and San Antonio, has written a noted book on gunshot wounds. He offered a theory on the shooting.

"In my opinion, the physical evidence is she had the weapon," he said. "She's the one who fired the gun. He didn't have the gun. She fired it and probably didn't think of the consequences. It was a spontaneous reaction of some sort. Stupid. Based on alcohol. If she'd thought about it, she would have probably put it down."

DiMaio insisted that his portrait of Clarkson as an aging, down-on-her-luck actress with dismal career prospects was a minor consideration in reaching his opinion. But Jackson persisted in revisiting DiMaio's comments about Clarkson being depressed over her fading career.

She had brief fame in the 1980s as the star of a cult movie, "Barbarian Queen." DiMaio said e-mails showed that she was depressed over her failure to get work.

In response, Jackson projected on a courtroom screen dazzling professional photos of Clarkson showing her in glamorous poses, head shots intended to promote her career.

"She's a very beautiful girl," the witness conceded. "And she's 40 years old and there a lot of people after the same jobs she was. It's a hard life for an actress. That's Hollywood. ... She's competing against younger girls. She's competing against Paris Hilton and things like that."

DiMaio stressed again that this career history played little role in his opinion but said he gave it because "my report has to be complete and cover all aspects."

Before concluding his testimony, DiMaio was challenged by Jackson on why he did not mention Spector's history of holding women at gunpoint. Citing the remote dates of the incidents which go back to the 1980s, DiMaio said it was not a significant factor in his conclusion.

"Physical evidence trumps history," he said.

Jackson pressed him on whether each piece of physical evidence — blood spatter, gunshot residue, the bullet wound — could just as easily be interpreted as showing that Spector fired the gun.

"Yes, if you take each in isolation," said DiMaio. "But each thing taken in isolation means nothing.

"The whole question in this trial is who fired the gun? ... The only thing that could answer the question is physical evidence, not the stories," he said.

If convicted, Spector could face 15 years to life in prison. The trial is to resume July 9.