SAN DIEGO -- Two ex-co-workers of a woman accused of poisoning her Marine husband testified Wednesday that she participated in wet T-shirt and thong contests a few months after he died, and three military men testified they had sex with her in the weeks after she became a widow.

Cynthia Sommer, 33, is charged with murder and special circumstances of murder by poison and murder for financial gain in the Feb. 18, 2002, death of Sgt. Todd Sommer.

Closing arguments are scheduled Friday.

Prosecutors theorize that the defendant -- a mother of four -- poisoned her 23-year-old second husband with arsenic so she could cash in on a $250,000 military life insurance policy.

Sommer -- who faces life in prison without the possibility of parole if convicted -- used some of that money to buy breast implants several weeks after the victim's death, according to trial testimony.

Dana Benton, who now lives in Cocoa, Fla., testified that she met the defendant at a Subway sandwich shop where they worked and socialized with her following the victim's death.

Benton testified that in April or May of 2002, she, the defendant and others went to a club in Tijuana, where Sommer participated in a wet T-shirt contest.

"She was up on the balcony with all the other contestants, wearing a wet T-shirt," the witness said, adding that Sommer later exposed her breasts in the club.

Benton told defense attorney Robert Udell that she thought Sommer was acting like a grieving widow, but was showing it in her own way.

She also said Todd Sommer knew about the defendant's plans to get breast augmentation surgery, but wanted her to lose 10-15 pounds first.

Another Subway co-worker, Chantra Wells, testified that Sommer also participated in a thong contest at the club in Tijuana.

Wells said the defendant was dancing around and eventually took her thong off and draped it over her shoulder.

Wells testified that Sommer came into work one day after the victim died and nonchalantly announced that her husband had passed away.

Sommer didn't act like something serious had happened, the witness testified.

Sommer's attorney told jurors at the start of the trial that his client lost the "man of her dreams" when her husband died. She met him after a failed marriage that produced three children, and they were married in 1999 and had a child together, according to the attorney, who said Sommer's "goal in life was to be the wife of a Marine."

Three men -- two Marines and one former Marine -- testified Wednesday that they had sex with the defendant in the weeks and months after her husband died.

Christopher Reed, who is now out of the military, testified that Sommer came over to his apartment and had sex with him while her young son was sleeping on a couch in another room.

A couple of weeks earlier, Sommer called him and told him that she and his wife were coming over to have sex with him, Reed testified.

He testified that he later saw a Marine -- who is now the defendant's fiance -- driving the victim's car, which upset him.

Todd Sommers' death was originally classified as resulting from natural causes, but a subsequent test for heavy metals in 2003 showed arsenic levels more than 1,000 times the normal level in his liver and 250 times above normal in his kidneys.

Sommer told agents from the Naval Criminal Investigative Service that her husband got "violently ill" on Feb. 8, 2002, 10 days before his death.

She told investigators that the Marine sought treatment, eventually recovered and went back to work but complained the night before he died that his heart was fluttering, according to Deputy District Attorney Laura Gunn.

The day after Todd Sommer died, his wife got a $6,000 death gratuity payment from the military, and a month later, she received more than $250,000 from his military life insurance policy, the prosecutor said.

In 2001, Gunn said, the military turned down the defendant's application for a loan because they said she wasn't living within the family's means.

A trust fund in Todd Sommer's name was also drained by Jan. 31, 2002, the prosecutor said.

On Feb. 8, 2002, the defendant consulted a plastic surgeon in La Jolla for breast augmentation, and two months later paid $5,400 for the procedure, according to the prosecutor, who said Sommer lied when she said her husband went with her to the Feb. 8 appointment.

In his opening statement, Udell said there would be no evidence presented at the trial that connects his client to arsenic.

Defense experts subsequently testified that the victim should have had large amounts of arsenic present in other body parts if he was poisoned, while prosecution witnesses testified that they were easily able to purchase arsenic online.

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

A 911 call placed by the defendant was played for jurors, in which his wife is heard to say, "Honey, I love you. Don't do this to me. What am I going to do without you?"

Udell said his client lost benefits and free housing after her husband died.

"The evidence will show Cindy Sommer did not benefit financially from Todd's death," Udell told the jury. "The evidence will show that Todd was the best thing that ever happened to her."