A competent botanist can estimate the age of vegetation found under a body in relation to foliage found in the immediate surrounding area. In one case, a skeleton found in wet Massachusetts ground had become intricately intertwined into a wild network of shrubs, weeds and vines. The evidence was delivered to investigators in two huge blocks of earth! In fact, when the crates arrived, someone said “. . . Along with the bones, they’ve sent us a couple acres of Massachusetts real estate.”
Although examiners like to see the remains—in situ—in the exact same relation it had to the field, this was second best. A careful study of the root system provided them with data on time since death, simply because investigators could determine how many growth seasons had passed.
Also, botanists know that when a root penetrates a bone it keeps growing, and the new developing stems can ultimately break the bone into fragments, imitating other forms of trauma. It would have been impossible to identify the sites of bullet impact on the bones if it had been confused with similar destruction due to later root growth.
Pods, seeds and pollen can also be conclusive evidence. In Arizona a woman’s body was found in the desert under a paloverde tree. Police arrested a suspect who had two paloverde seedpods in the bed of his pickup. Since DNA testing can match parent plants just like DNA on human parents matches their children, the tests proved that the seedpods from the man’s truck matched the tree under which the woman’s body had been found. This living evidence helped to convict the man of murder.
In another case, seeds in a 1960 murder investigation told investigators that the corpse had been moved from the actual murder scene. A cypress tree found in a garden of a particular house also matched seeds and mortar found on the body, pointing police in the right direction. Further evidence built a solid case against a man who was eventually convicted of murder.
Palynology is the study of palynomorphs or pollen. The best thing about pollen besides evidence of the seasons, is that pollen has a predictable production and dispersal rate in specific regions. Consequently when it is found on material at crime scenes, it can lead to a suspect.
Some palynologists believe that O.J. Simpson, a man who was acquitted of killing his wife and an innocent bystander, could have been linked to the case with pollen evidence. If, in fact, Simpson had hidden in the bushes as theorized, his clothing might have picked up pollen spores, placing him at the scene. Pollen evidence found in dirt helped to convict a murderer in Sweden in 1969. In one Austrian case, mud on the killer’s boots linked him to a crime scene, and, once a detective even found pollen in the grease of a killer’s gun and another found pollen in the ink of a document that demonstrated it was a forgery!
Some excerpts from Andrea's book Detective Notebook: Crime Scene Science, for children ages 10 and up.