Tiny Clues from a "Gentle Drowning"

In 1983 the National Institute of Justice put up the funds for the two professors to publish a slim volume of photos?a botanical field guide to the pathologist's garden. Among its eerily beautiful micrographs: the sharp-angled, stone-like cells that identify a bite of pear, the amoeba-like oil droplets of a chewed olive, and the pouting, oversized pores of a spinach leaf.



Bock and Norris hoped their limited edition would encourage American pathologists to make their own identifications. Instead, it brought a stream of new deliveries to their laboratory: vials of stomach contents removed at autopsy, swatches of clothing and bedding encrusted with vomit.



As to the Merced toddler murder: Would it be a far reach, Wilkerson asked Bock, to analyze not vegetables but water from a drowned child's stomach? "We immediately saw the potential," says Bock. Just as plants colonize land, algae thrive in aquatic environments. Kelp is a familiar, macroscopic example of this plant-like group. Even more ubiquitous are the glassy, one-celled algae known as diatoms.



Bock photographed the water samples under a microscope. Each drop brimmed with scores of diatom species?each with its own jewel-like shape and intricately ornamented cell wall. It didn't take long to determine that the toddler's stomach contained water from both fountain and stream.



The implication: The child had been held underwater in the fountain pool before being tossed?dead or nearly so?into Bear Creek. Told of the finding, the teenage mother confessed.



Success stories only increase the consulting burden for Bock and Norris, but the analysis of gastric contents is just one of botany's many forensic applications. Though forensic botany remains a rare specialty in this country, its practitioners have located hidden graves by recognizing signs of disturbed plant growth, pinpointed the geographic location of kidnap victims from the background foliage in photographs, used shreds of plant evidence to place suspects at the scene of a crime, and estimated time of death by determining the age of weeds growing among human remains. Yet botany remains below the radar of most forensic investigators.



"It's frustrating," says Bock. "Every forensic lab should have someone with the basic training to make sense of botanical evidence. After all, it's cheap, it's easy, and all you need, for the most part, is an ordinary light microscope."



Perhaps plant work is too low-tech in an age that glorifies computer analysis and DNA fingerprinting. Bug-focused forensic entomologists at least have the creepiness factor going for them: The more nauseating episodes of CSI have popularized the idea of using maggots as evidence. Then again, Court TV recently approached Bock about dramatizing one of her more sensational cases. She and Norris are also hammering out the early chapters of their field's first handbook, Forensic Botany.



Meanwhile, perhaps the National Institute of Justice would do well to publicize the importance of eating veggies at every meal. Some of us will live longer; others might at least point a green finger, from the autopsy table, at our killers.