This is scientific American 60 second science.

I'm Christopher Intagiyata.

As soon as a person dies, decomposition begins,

and the first visitors arrive.

Within five to 15 minutes of death,

blow flies or other insects begin to colonize the body.

Robbie Musa, an organic chemist at the University of Albany. She says different species turn up at different stages of decomposition.

So because of that, depending upon what entomological evidence you find,

you can learn something about when the person died

in terms of the timing of the death.

Flies don't tend to stick around when disturbed

by detectives, for example,

but they do leave behind eggs.

The eggs are hard to tell apart by appearance alone.

So forensic entomologists rear them until they hatch a few weeks later.

And they get a species ID, and with a little guesswork, a person's time of death.

But Musa has come up with a less time-intensive approach,

chemical analysis of the eggs.

She and her team investigated that method by first harvesting flies with pig liver traps, stashed throughout New York City.

So it turns out that it's easy to hide pig livers in various parks and whatnot in Manhattan. There's a lot of foliage and

whatnot and so they're easy to hide so no one knew. They collected the

trap flies and then chemically analyze their eggs.

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