I rather forgot about the tree until I got back home. One day in the library, I decided to try to track down the story. I didn't have any luck, but it was probably because I just hadn't spent enough time at it. In addition, I knew there was another way to search: The Internet.
Lately, I had seen reference to a method of posting questions to Usenet newsgroups via e-mail. Now here was a good opportunity to test this out. The newsgroup which I felt would be the best place to post my query was bionet.plants. I wrote up and sent a brief message, and sat back to see what would happen.
The next time I checked my mailbox - an hour later - I saw a message from the mailer-daemon, a notice of mail delivery failure. It wasn't looking good for this posting-by-e-mail business! However, there was another message waiting as well, with the subject heading of: Re: Tree that helped to solve a murder.
Someone in Missouri was telling me the name and e-mail address of the botanical sleuth at the University of Arizona who had linked the seed pods that had been found in the truck of a murder suspect to a particular Palo Verde tree near where the body of a murder victim had been found! Three more similar responses arrived within the next twenty-four hours, in addition to one that was actually posted in the newsgroup. And not a single flame to berate me for not having been able to come up with this information on my own!
Still haven't figured out what that mail delivery failure notice was actually trying to tell me - but I guess I won't be worrying about it!
Reference: Science, Vol. 260, 14 May 1993, p. 894-895.
Angiosperm Witness for the Prosecution
For the first time a murderer has been convicted on DNA evidence obtained from a plant. The case was described in the PBS TV series, Scientific American Frontiers, amiably hosted by a continually bemused Alan Alda, the perfect foil for the scientists he interviews. The murder of a young woman occurred in Phoenix, Arizona, and the finding of a pager at the scene of the crime lead the police to a prime suspect in the case. He admitted picking up the victim, but claimed she had robbed him of his wallet and pager. The forensic squad examined the suspect's pickup truck and among the bits of evidence collected were pods later identified as the fruits of palo verde (Cercidium spp.). One detective went back to the murder scene and found several palo verde trees, one of which showed some damage that could have been caused by a vehicle. The detective's superior officer innocently suggested the possibility of linking the fruits and the tree by using DNA comparison, not realizing that this had never been done before. Several researchers were contacted before a geneticist at the University of Arizona in Tucson agreed to take on the case. Of course, the first crucial study was to establish evidence that would stand up in court on whether individual plants (especially the palo verde trees) have unique patterns of DNA. A preliminary study on samples from different trees from the murder scene and elsewhere quickly established that each palo verde tree was unique in its DNA pattern. It was then a simple matter to link the pods from the suspect's truck to the damaged tree at the murder scene and obtain a conviction.
WNED-TV (PBS - Buffalo, N.Y.), January 19, 1994
From: http://www.uoguelph.ca/botany/cba/PLPR942.htm