An Invisible Enemy

New Developments In The Case Of A Young Marine Who Died Suddenly - Was It Natural Causes Or Poison?

This story previously aired on Feb. 7, 2009. It was updated on June 27.

It was February 2002 when Cynthia Sommer, her husband, Marine Sgt. Todd Sommer, and their four children were coming home from a family weekend at an amusement park.

But as Richard Schlesinger reports, no one could have predicted the rollercoaster ride was just beginning.

"Came back home on Sunday, got the kids to bed. And he said that his heart felt like it had fluttered," Cynthia recalls. "I said 'Should we go to the hospital?' He said 'No, I'm fine. I'm just gonna go to bed.'"

Hours later, Cynthia made the panicked 911 call.

When Todd was pronounced dead a couple of hours later at the hospital, doctors said his heart had given out.

"They explained it the same as - you hear of kids playing baseball and just falling over, that there's no symptoms, there's no warning sign, there's nothing,'" Cynthia remembers.

But there was something: Todd had started feeling sick 10 days before he died. His symptoms started on Friday, Feb. 8.

"Saturday, he started vomiting - had diarrhea, nausea, some stomach cramping. It sounded like food poisoning."

On Sunday, Todd went to the Marine base clinic. A doctor thought it might be food poisoning and told him to wait it out. When his symptoms got worse, Cynthia turned to her mother for advice.

"The conversation would be, 'Mom, Todd's fever is up to 102. What should I do?' And, 'I just can't stop him from throwing up,' and, 'What else can I give him?'" Jan Lippert remembers. "I'd tell her the usual mother's remedies. And nothing seemed to help."

Todd went back to the doctor two days later. Cynthia says they gave Todd IV fluids and prescription medications.

And by that Saturday, Feb. 16, he seemed to be finally getting better. Todd felt well enough to go on that family outing to the amusement park.

But 48 hours later, he was dead. The official cause of death: cardiac arrhythmia.

Cynthia's mother rushed to be by her daughter's side. "It was a scene that I will never in my entire life ever forget… She was upstairs in their bed and she had one of Todd's shirts," Jan recalls. "She was just clinging, just clinging onto his shirt, and saying how it smelled like Todd and this is all she had left of him, that he was gone."

Todd and Cynthia had met just three years before Todd died. He was 19 and Cynthia, a divorced mother of three, was 25.

"I finally found someone that wanted to be a friend," Cynthia says. "I found someone that I could -- wanted to share my life with."

Within six months, Todd and Cynthia were married and living in San Diego where Todd was stationed. And before long, the newlyweds added another child to the family.

"We were a great family. And the kids loved him. I loved him," Cynthia says. "We did family things all the time."

But it all ended in an instant when Todd died. The Naval Criminal Investigative Service (NCIS) opened a routine investigation into Todd Sommer's death. As the investigation began, NCIS agents found nothing suspicious.

Lippert says her daughter began to face life as a widow. "She wanted to go on and make the most of her life and do it as best as she could."

It didn't take long. Cynthia found a new boyfriend and moved to Florida with her four children. Officially, there was no mystery about how Todd had died. The death certificate said natural causes. But one investigator couldn't shake a bad feeling.

NCIS Special Agent Mark Ridley was in charge of what the service calls a death review panel. It's the way the NCIS makes sure that all leads are pursued in military deaths, especially when someone, like Todd, dies unexpectedly.

"There were some odd things goin' on with the investigation that I thought needed additional work," he says. "They were lookin' at the case as being a natural death from the beginning."

Ridley felt the autopsy had overlooked important clues -- those symptoms Todd was suffering in the days before he died. "When you look through the medical record it showed that he had vomited several times, maybe 12 to 15 times in the space of a short period of time," he says.

Ridley thought those symptoms and Todd's sudden death were related. And it all started sounding familiar. The special agent had heard about a similar case in North Carolina and in that case the victims had been poisoned.

"It just so happens that Todd Sommer was exhibiting some of the same things that were found in some of the victims associated with the case," he says. "It resonated with me and when I read that case file it just made me a little bit uncomfortable, based on the symptoms."

Ridley was not ready to close this case. He ordered a rare heavy metals test be performed on Todd's tissue samples, which had been removed during the autopsy.

Meanwhile, NCIS Special Agent Rob Terwilliger started looking into Sommer's personal life." Going from the day Todd Sommer died and looking at every report, every note, every scrap of paper that was in the case file."

Terwilliger dug deeply into Todd's relationship with his friends, his family, and his outwardly grieving widow. "More and more information came out indicating that his relationship with his wife was not what it seemed."

The picture the NCIS was painting of Cynthia Sommer was less than flattering.

"Cindy was more of a party girl, was having financial difficulties when Todd was away on deployment," Terwilliger adds.

The more Terwilliger studied the Sommer family finances, the worse it looked for Cynthia. He quickly discovered she was spending more money than they had -- but it was more what she was looking for. The same day Todd got sick, Cynthia apparently met with a surgeon, inquiring about breast implants.

At the time, the Terwilliger says the couple had about $150 in their bank account. The breast implants would cost nearly $6,000, and would be a huge financial strain on the family.

Cynthia says Todd wanted her to have the operation and has a note on a Valentine's Day card from him that she says proves that. In 2006, she told 48 Hours that she went ahead with the surgery just two months after Todd died.

"After he died, I just… I wanted to escape everything… I know if he were alive and he had that much money, he would have wanted me to do it."

Nearly two and half years after Todd's death, the results of the tests on his tissue samples came back. They showed Marine Sgt. Todd Sommer had been poisoned with a lethal dose of arsenic. But was it murder?