It was one of those days in March when spring is in the air. The daffodils are up. Cherry blossoms are beginning to bud.

The young chemist trudging across the Walter Reed Army Medical Center campus that morning

would probably have wanted to savor the moment, because once he entered Building 54, home to the Armed Forces Institute of Pathology,

he knew he would be completely shut off from the outside world.

Unlike those quaint Rose Brick Georgian buildings elsewhere on the Walter Reed campus,

Building 54, well, this place was unique, unlike any other building on campus. Indeed, unlike any in the

country. Building 54 is a massive five-story white block with three basements below ground,

not a window or decorative curlicue on it.

With steel blast-proof doors and walls that were two feet thick,

Building 54 was built in the 1950s to survive a hydrogen bomb blast, to be a presidential

refuge if it came to that. Grim and graceless, all of the above. Just inside, the building contained brightly lit labs that were a pathologist's dream.

All the best equipment.

There was a brand new tissue analyzer, clunkily named inductive coupled plasma mass spectrometer.

Very expensive. There were microwave digestive systems

for prepping samples, top-notch chemicals and compounds, high purity reagents. All of it was intended

to help the military pinpoint toxins, contaminants, and environmental risks that might threaten

the nation's soldiers, sailors, Marines, and airmen.

After buzzing through security on that spring day in 2003, the chemist, Todor Todorov,

took the elevator down to the basement, to his lab,

the Department of Environmental and Toxicologic pathology.

It was there he would spend months analyzing tissue samples

that had been harvested from the body of Marine Sergeant

...