SAN DIEGO -- A toxicologist testified Monday there were several inconsistencies in tests done by a military laboratory that revealed lethal levels of arsenic in the organs of a Miramar-based Marine whose wife is accused of murdering him.

The testimony in the murder trial of Cynthia Sommer, who is accused in the Feb. 18, 2002, death of Sgt. Todd Sommer, came as her defense team called its last witnesses.

Prosecutors theorize that the 33-year-old defendant -- a mother of four -- poisoned her husband so she could cash in on a $250,000 life insurance policy.

Sommer used some of that money to buy breast implants several weeks after the victim's death, according to prosecutors.

The 23-year-old Marine's death was originally classified as resulting from natural causes, but a subsequent test for heavy metals in May 2003 showed arsenic levels more than 1,000 times the normal levels in the victim's kidneys and liver, according to the prosecution.

Laura Labay, testifying for the defense, said her employer, NMS Labs of Willow Grove, Pa., was asked to retest some of the victim's tissue samples that were previously tested by the Armed Forces Institute of Pathology, which originally found the lethal levels of arsenic.

Labay said sample identification and chain-of-command methods used by AFIP were "unacceptable."

The witness, who is not a medical doctor, testified that other tissues in the victim's body should have had large amounts of arsenic present.

Labay also said she would have expected to see abnormal lab results from the victim two days after he started have symptoms on Feb. 8, 2002.

Those lab results at Miramar were normal, and he gradually got better in the 10 days before he died, according to court testimony.

Labay questioned whether the victim got one large dose of arsenic around Feb. 8.

"It is not conceivable that he walked around for 10 days without being ill," the witness said.

Deputy District Attorney Laura Gunn told jurors in her opening statement that the defendant was the only adult close to the victim when he got sick.

Defense attorney Robert Udell has said Gunn would not be able to show that the defendant gave her husband any arsenic.

The attorney said earlier that fellow Marines who accompanied the victim on a Feb. 8, 2002, trip to El Centro, said he ate some egg rolls on the way home, which Udell suggested were the cause of his illness and subsequent death.

Udell also told the jury that his client did not benefit from her husband's death.

A Miramar Marine testified for the defense that the defendant had only one loud party after her husband died.

When asked by the prosecutor if he was aware that Sommer had sex with four different Marines in the weeks after the victim died, the witness said no.

Sommer, who was arrested in late 2005, is charged with murder and special circumstances of murder by poison and murder for financial gain. She faces life in prison without parole if convicted.

The defense is expected to call a final witness Tuesday, with rebuttal witnesses from the prosecution to follow.

Closing arguments could be given as early as Wednesday.