Death Du Jour

“Maggots mature rapidly, and when they reach maximum size they undergo a dramatic change in behavior. They stop feeding and look for drier digs, usually away from the body.”

“Act three.”

“Yep. The larvae burrow in and their outer skins harden and form protective encasements called puparia. They look like tiny footballs. The maggots stay inside the pupal casings until their cells have reorganized, then emerge as adult flies.”

“That’s why the empty puparial cases are significant?”

“Yes. Remember the flesh flies?”

“The Sarcophagidae. The larvipositers.”

“Very good. They’re usually the first to emerge as adults. It takes them anywhere from sixteen to twenty-four days to mature, given temperatures around eighty degrees Fahrenheit. They’d be slowed under the conditions you describe.”

“Yes. It wasn’t that warm.”

“But the empty puparial casings mean some of the flesh flies had finished their development.”

“Flown the pupae, as it were.”

“It takes the blowfly about fourteen to twenty-five days to mature, probably longer in the wet environment on your island.”

“Those estimates tally.”

“You also collected what I’m pretty sure are Muscidae larvae, maggots of the housefly and its relatives. Typically these species don’t show up for five to seven days after death. They prefer to wait for what we call the late fresh or early bloat stages. Oh, and there were cheese skippers.”

Cheese skippers are maggots that jump. Though not always easy, I’ve learned to ignore them while working on putrefied bodies.

“My personal favorites.”

“Everybody’s got to make a living, Dr. Brennan.”

“I suppose one has to admire an organism that can jump ninety times its body length.”

“Have you measured?”

“It’s an estimate.”

“A particularly useful critter for estimating PMI is the black soldier fly. They don’t usually show up until twenty days after death, and they’re fairly consistent, even with buried remains.”

“They were present?”

“Yes.”

“What else?”

“The beetle assemblage was more limited, probably due to the wet habitat. But the typical predator forms were there, no doubt munching happily on the maggots and soft-bodied forms.”

“So what’s your estimate?”

“I’d say we’re talking about three to four weeks.”

“Both bodies?”

“You measured four feet to the bottom of the pit, three feet to the top of the lower body. We’ve already discussed the preburial larviposition by the flesh flies, so that explains the puparial cases you found on and above the deeper body. Some held adults, half in and half out. They must have been trapped by the soil while trying to exit. The Piophilidae were there, also.”

“Lou?”

“Cheese skippers. I also found some coffin flies in the soil sample you took from above the lower body, and some larvae on the body itself. These species are known to burrow down to corpses to deposit their eggs. The soil disturbance in the grave and the presence of the upper body would have facilitated their access. I forgot to mention I found coffin flies on the upper body.”

“Were the soil samples useful?”

“Very. You don’t want to hear about all the critters that chow down on maggots and decompositional materials, but I found one form that’s helpful with PMI. When I processed the soil I collected a number of mites which support a minimum time since death of three weeks.”

“So you’re saying three to four weeks for both bodies.”

“That’s my preliminary estimate.”

“This is very helpful, Lou. You guys amaze me.”

“Does all this square with the condition of the remains?”

“Perfectly.”

“There’s one other thing I want to mention.”

What he told me next sent an icy wind rocketing through my soul.