updated 5:55 p.m. ET June 3, 2007

LOS ANGELES - A coroner testifying in Phil Spector’s murder trial acknowledged there were crime lab mistakes in evidence collection and handling including moving Lana Clarkson’s body, which ended up compromising evaluation of at least one item at the crime scene.

Dr. Louis Pena also said Wednesday during cross-examination by Spector’s defense attorneys that medical findings could not determine who held the gun that fired the bullet that killed the actress.

Spector, 67, is accused of shooting Clarkson, 40, on Feb. 3, 2003, after she agreed to accompany him to his mansion from her job as a hostess at the House of Blues on the Sunset Strip.

The defense is seeking to show that Clarkson pulled the trigger of the handgun inserted in her mouth.

“Let’s get it very basic,” defense attorney Christopher Plourd said Wednesday. “You can’t tell who was holding the gun.”

Robyn Beck / AP Dr. Louis Pena, a deputy medical examiner, testifies during cross-examination in the Spector murder trial.

“That’s correct,” Pena replied.

Pena said Clarkson had gunshot residue on both of her hands and that he classified the case as “pending” until he finally signed off on it and entered a death certificate on Sept. 19, 2003. But the residue didn’t necessarily mean she fired the gun, he said.

“There are two ways to look at it,” said Pena. “It implies the person could have been holding a weapon at the time of discharge or could be in the vicinity.”

On Tuesday, Pena was unequivocal that Clarkson’s death was a homicide. He testified there was no evidence Clarkson had been putting her affairs in order in advance of a suicide, and he described the actress as a hopeful person with no history of depression or suicide attempts.

He said she had a bruise on her tongue indicating a trauma, possibly from the gun being shoved in her mouth, and had recent bruises on her right arm and hand. He said Wednesday he didn’t consider the tongue bruise significant until prosecutors raised the matter recently.

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The medical examiner also said criminalists made mistakes in evidence collection and handling, including the loss of a piece of one of Clarkson’s teeth.

The missing tooth fragment was among items in an in-house coroner’s office memo about concerns in the case.

The memo also said a criminalist used lift-off tape on Clarkson’s dress to collect samples of evidence and inadvertently compromised investigators’ ability to evaluate blood spatter on the dress.

Pena acknowledged during cross-examination that Clarkson’s body was mistakenly moved, causing blood to flow from her mouth, compromising evaluation of her dress for blood spatter.

Spector rose to fame in the 1960s with what became known as the “Wall of Sound” recording technique that changed pop music. Clarkson was best known for her role in Roger Corman’s 1985 cult film “Barbarian Queen.”

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