A judge ordered a new trial Friday for a woman who was convicted of poisoning her Marine husband with arsenic and then using his life insurance to pay for breast implants.

The judge found that Cynthia Sommer, 34, received ineffective representation from her former defense attorney. San Diego Superior Court Judge Peter Deddeh said the lawyer's errors allowed prosecutors to introduce evidence about Sommer's wild partying immediately after the sudden death of her 23-year-old husband.

Sommer's former attorney, Robert Udell, told the judge that he committed tactical errors, including a failure to call witnesses to adequately refute prosecutors' theories about the source of the arsenic.

Deddeh said Udell's choices undermined his confidence in the verdict.

Udell did not respond immediately to a telephone message after the ruling.

Sommer, who remains in custody without bail, was convicted in January of first-degree murder by poisoning and for financial gain. She faced a mandatory sentence of life in prison without the possibility of parole if Deddeh had denied the retrial.

Her current attorney, Allen Bloom, said he plans to request bail conditions at a hearing set for Dec. 12 in San Diego.

Sgt. Todd Sommer was in top condition when he collapsed and died Feb. 18, 2002 at the couple's home on the Marine Corps' Miramar base in San Diego after a family trip to the Knott's Berry Farm amusement park. His death was initially ruled a heart attack. Tests of his liver later found levels of arsenic 1,020 times above normal.

Sommer's co-workers testified during the trial that the widow didn't grieve quietly in the weeks after her husband's death. Rather than going into seclusion, she got her breasts enlarged and, witnesses said, joined wet T-shirt contests at nightclubs and had casual sex with other military men.

Prosecutors said Sommer wanted a more luxurious lifestyle than she could afford on the $1,700 monthly salary her husband brought home and saw the $250,000 military life insurance policy as a way to "set herself free."

The case turned on circumstantial evidence of Sommer's financial debt and later spending sprees to show that she had a motive to kill her husband.

Sommer's in-laws testified that she objected when they asked her to put her husband's death benefit in trust for herself, their baby and her three children from a previous marriage instead of spending it right away.

Sommer, who moved to Florida after the death, cried when called to the stand Jan. 17, dabbing her eyes as she recounted her husband's final moments. But she also said during cross-examination that she hadn't been able to envision a future with the Marine. The pair married in 1999.