What a grim task, recovering a body from the bottom of a pond. This was a farm pond, less than 100 yards from the house. The body was that of a four year old boy, the only son of the couple who owned the farm.

"I told him to never go near the water unless we were with him," the father told detectives. The parents said they planned to take him to swimming lessons next summer.

The small body was taken to the morgue and in a few days the coroner made his ruling: "death by drowning." The case was closed.

Darrell and George, two detectives I’ve mentioned before, had uneasy feelings about this case. Something wasn’t right. On a hunch, they quietly canvassed people who knew the couple.

The comment that surfaced most frequently was, "the boy’s daddy had a mean temper."

"So what," says George, "I’ve got a mean temper-lots of people have a mean temper. Does that mean the boy was killed?"

"No, it doesn’t," says Darrell, "but we need to take a closer look and make that uneasiness go away."

For the next few nights George spent several hours each night surfing the World Wide Web looking for information on drowning victims. He found what he was looking for.

The detectives presented their new information to a forensic pathologist. After another examination was completed, the pathologist reported, "the boy was dead before his body entered the water. He did not drown!"

After lengthy questioning, the father finally admitted that he had thrown the lifeless body of his son into the pond in an effort to conceal his crime.

How did the detectives know?

Algae from pond scum contain elements known as "diatoms." These microscopic particles enter the body through the lungs and eventually find their way into the marrow of the bone.

No "diatoms" were found in the dead boy’s bone marrow. He was dead before his body hit the water. The boy was murdered.