Leona Meikle was on the phone, answering the oddest questions. With each one, she was beginning to understand how hard it would be to find the answer to her son's death.

On the other end of the phone was a nurse from the Minnesota Department of Health who was gathering any and every bit of information that might hold the key to Reece's death weeks earlier.

Had Reece been out of the state before he died? the nurse asked Leona.

Yes, to North Dakota.

Spent time on a farm?

Yes, his aunt's.

Had close contact with rodents? Dead birds?

Well, he had killed a bird with a paintball gun and then buried it. And he and his brother found a dead skunk on the farm.

Any herbal remedies?

No.

Had he eaten any shellfish?

Leona turned to her other sons, Payne and Grant, sitting near her. Sort of, she told the nurse. He had taken a bite out of an octopus he was dissecting in science class.

Had he used alcohol or other drugs before he got sick?

No, she said.

The nurse was a disease investigator for the Unexplained Critical Illnesses and Deaths Project, which is run by the Minnesota Department of Health and the Centers for Disease Control and Prevention. Since 1995 disease investigators have looked into 86 deaths in Minnesota like Reece's -- sudden, mysterious deaths that looked like they had been caused by an infection.

His was one of the most mysterious of all. He was 15 years old, and teenagers are almost always resilient enough to withstand even the most aggressive infections. Then there was his blood, which had turned to sludge inside his body. And finally there was the possibility that it wasn't an infection that had killed him. It may have been his body's reaction to an infection that killed him.

Each of the state's 86 unexplained deaths was treated as if it was the next Legionnaires' disease, AIDS or toxic shock syndrome, or the first death in a worldwide pandemic. Because each one might have been.

And Reece, too, might have been the first victim of the next new disease or some dangerous variation of an old one.

•••

As Leona patiently answered the nurse's questions, machines at the Health Department were hard at work analyzing tissue and blood samples from Reece. One machine amplified fragments of genetic material from viruses and bacteria until they were large enough to identify.

Scientists tagged the antibodies in Reece's blood samples with fluorescent markers to see if they reacted to various infectious agents. If the antibodies attacked, then Reece had that infection.

Because Reece had spent so much time outdoors, they looked for germs transmitted by animals and insects, especially tick diseases. They also looked for whooping cough, Legionnaires', two kinds of pneumonia and four kinds of flu.

In the last decade the technology to find and identify infections has become much more sophisticated. Disease investigators can now solve mysterious deaths and illnesses that happened years ago.

But mysterious deaths still go unsolved more often than not. In 2004 Minnesota investigators looked into 18 such deaths, including Reece's.

They solved four.

In Reece's case, scientists conducted 141 tests for 18 types of infectious diseases.

They found two.

One was pneumonia -- a type often found in young people. But his blood had been so diluted by transfusions and his red cells were so badly clumped that scientists could not really be sure of what they found.

The second was a virus for the common cold.

Neither one has ever been known to cause a death like Reece's.

•••

At the end of July 2004, Leona sent out an e-mail to her family.

"Here is the latest," she wrote. "They have run hundreds (many, many) tests on Reece. All have been negative except two, which are of no help in determining the cause of death. ... They say they are in completely uncharted waters now."

The uncertainties continued to eat at her. The questions from her family and friends and her own fears built up inside of her, layer by layer. Could it be this disease? Or that disease? Was it catching? Could it be something in the water?

At the end of August, she and her husband, Roger, sat down across a conference table from Dr. Dennis Drehner and Dr. Yoav Messinger. Leona was ready. She needed certainty, even if it was only certainty about what hadn't killed Reece.

She laid her list of questions in front of her on the conference table.

"West Nile?"

"Uh, no," Drehner said.

"Absolutely ruled out?"

"Right," Drehner said.

"OK, toxic shock?"

Drehner shook his head. Toxic shock is known for creating massive inflammation in the body or by easily identified bacteria, he said.

"Meningitis?"

Reece didn't have massive inflammation in the covering of his brain, the hallmark of the disease, Drehner said.

The last item on her list was the one that had scared her the most. She knew it wasn't a reasonable fear, but she couldn't shake it.

"His wrist surgery," she said. Months before Reece died, a surgeon had put a metal pin in his wrist to repair a fracture. It was elective, Leona knew. The bone would have healed without it. In her mind, it had become one of those simple choices that haunted her. What if it had been the pin?

Messinger shook his head. Orthopedic metal is inert -- the body doesn't react to it. But they would check it out and make certain, Drehner said.

"So more to come on the wrist surgery?" Leona asked.

There was no question that wasn't worth asking, even the remote ones, Messinger said. "I'm serious," he said. "I don't want you guys to have any possibilities ... stuck in your brains."

Leona hesitated. She had two more.

Would Reece have lived if they had brought him to the hospital two days earlier? And would he have lived if doctors had given him the last treatment -- cleaning his blood in a machine -- first?

"I've asked myself that how many times," Messinger said.

Messinger, too, had been haunted by doubts. Just like Leona, he had lain awake nights thinking about mistakes he might have made, clues he might have missed. Over and over he had relived all the decisions made in Reece's case, but he always came back to the same answer, the one he gave Leona.

"I don't think it would have made a difference," he said. There was no way to stop the relentless process of the disease.

Roger was silent, his big hands folded in front of him as they had been for the entire meeting. But inside he was astounded by what he had just heard. Someone might as well have put a gun to Reece's head and pulled the trigger. Death had been that certain.

Months had passed. Hundreds of tests had been conducted. Bits of his son's body had been sent across the country. Roger had never doubted that all those scientists with their remarkable brains and amazing technology would find the answer to his son's death. But they were clutching at straws.

As Leona got up to leave, she felt lighter.

The investigation wasn't yet over, and she still didn't know why Reece had died. But she was sure of one thing -- it wasn't going to be simple. And it wasn't some random decision of hers that had led to his death.

She reached into her purse, pulled out a wallet-size photo of a smiling, curly-haired teenager and slid it across the table to Messinger.

"I want you to remember who he was," she said.

Coming Thursday: Beyond the reach of science.

ABOUT THIS STORY

A tip came into the newsroom: a teenager from Woodbury had died from Rocky Mountain spotted fever, a rare disease in Minnesota. The tip turned out to be false, but tracking it down brought reporter Josephine Marcotty to this story.

With the family's permission Marcotty spent more than a year reporting the story. She reviewed dozens of documents, including Reece Meikle's medical records and documents. She interviewed dozens of people, including Reece's parents, Leona and Roger Meikle; the physicians, nurses and hospital technicians at Children's Hospitals and Clinics of Minnesota and more.

A note on quotes: Statements within quotation marks were heard directly by the reporter. Quoted statements without quotation marks come from documents, reports, and/or the recollections of people who were there.

On the Web: Previous stories are at www.startribune.com/reece