Growing up on her family’s farm in rural Indiana, fell in love with plants. But she never dreamed that a career in botany would lead her to investigate homicides. Yet over the past decades, Bock – now at the University of Colorado, Boulder – has used “forensic botany” in about 100 crime cases, and has helped to develop the science of using vegetation in police investigations.
What was your first case?
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I taught a class on plant anatomy and out of the blue a Ben Galloway called. He said, “I’m an assistant coroner in Denver and I have a question: if I had plant cells from somebody’s stomach contents, could you tell me what plants might have been in that person’s last meal before they were killed?”. The victim was a young woman who had been stabbed to death. He asked if I could look at her stomach contents. I quickly told him no. I said it’ll smell bad and it’ll probably look disgusting and I’m a botanist, I’m not used to that kind of stuff. He said he would send me prepared slides, if I would just put them under my microscope.
Well, that hooked me. I thought about how distinctive the cells of things like celery and pears are. And after a bit of extra work, I saw that in the last meal of this victim there were cells of kidney beans and cabbage. Galloway said that was useful, because her last known meal had been at McDonald’s. This was in the 1980s, when McDonald’s was just straight hamburgers and French fries. He said that means she ate again.
This cleared the victim’s boyfriend?
Yes, it did. He had eaten lunch with her at McDonald’s, but had an alibi for later in the day. Eventually, it turned out to have been a serial killer. And this set me on the course, because Galloway told everybody: “I have this gal at Boulder that can do this stuff.”
Forensic botany is good at narrowing down the time of death. Why?
My colleague, David Norris, is an endocrinologist. He taught me how, in digestion, you chew up something and swallow it and it’s put into an acid bath in your stomach and wiggled around. And in a couple of hours, a valve opens and things move more or less en masse to your small intestine. Animal cells don’t hold up in that. But plant cells have these wonderful cellulose walls that are virtually indestructible by human digestion. There was one case, where these three children had eaten pizza and it was so recent that we could still smell the oregano.
“The coroner said, could you tell me what plants might have been in their last meal before they were killed?”
Why did that matter?
The father claimed that he’d fed the kids at 5.30 pm, let them play outside and put them to bed at 6.30. Then at midnight, after his wife got home, he’d left for his job as a salesman – loaded up his car with samples and took off. But the stomach contents showed that the children had just eaten before they were killed. His wife was murdered too. The man was found guilty of killing them. But he was retried and found innocent the second time. That’s the only major case I can think of where our evidence didn’t work. A horrible experience.
Is it true that you often bought vegetables in the early years and chewed them up yourself, so that you could compare that to what you found in a victim’s stomach?
That’s right. Or we’d trick a grad student into chewing stuff and then submerge it into an acid bath and put it on a shaker to imitate the stomach movements. Our colleagues felt that this work was weird.
Can forensic botany also tie a person to a place?
Yes. For example, the vegetation of the tundra above the treeline here in Colorado is different from what’s in the foothills of the Colorado Rockies. So, if somebody claims to not have been up above the treeline, but we find tundra vegetation on the vehicle or the clothing, that’s powerful evidence that the person is lying (see “Case studies“).
Do you think about the crime when you look at the cells under the microscope?
When we get the samples, we can spend some time talking about the case and feel pretty bad about it. Then we start to work and it’s like anything else a scientist does, and we get really interested. We just love that we have a problem to solve. The next part comes when we hand in our report. And then the trial. That’s rough. If it’s a homicide, you usually look at the surviving members of the victim’s family in the courtroom. Then there’s the suspect, sitting there. And you know that if a verdict is reached, lives are going to be upside down and backwards. I find that very difficult.
Yet you keep doing this work?
It’s so interesting. And Dave Norris and I are both Midwesterners. All our lives we’ve dealt with family and fellows in our home towns who asked, “What you’re doing – what is it good for?” And, boy, is that easy to answer when you’re doing forensic stuff. As Dave says, sometimes our evidence is a waste of time, it doesn’t help. Sometimes it adds to other evidence, suggesting a possible solution to the case. And sometimes it’s spot on, it’s the most important clue.
Case studies
Golf course killing
After a night of heavy rain in late 1999, the body of Samantha Forbes was found on a golf course in Freeport in the Bahamas. Her throat had been cut. However, the storm had washed away any footprints, clothing fibres or other evidence that might have helped identify her killer.
But investigators discovered bits of grass on the socks and shoes of one of the two men who had been seen leaving a bar with Forbes the night before. Jane Bock identified the grass as almond Bermuda, which grew only on one of the island’s three golf courses — the one where Forbes was killed. This helped put one of the suspects at the scene and led to the conviction of both men.
Hash browns
Jill Coit married 11 times. She had separated again – and moved in with a new boyfriend – when previous husband Gerard Boggs was found clubbed, tasered and shot in his home.
Initially, it wasn’t clear when Boggs had died. But he always ate the same breakfast at a local diner: coffee, hash browns, toast and eggs. Bock and David Norris found traces of hash browns in Boggs’s stomach, indicating that he had died after breakfast. Coit and her boyfriend didn’t have an alibi for that time. Armed with Bock’s information, authorities obtained a search warrant for the couple’s home, where they found the murder weapons. Coit was arrested and convicted.
Forest forensics
Natalie Mirabal had been decapitated and her body left in the mountains of Colorado. Her husband claimed never to have been to that area in his truck. Police collected plant materials from inside the vehicle and sent them to Bock, who matched some of it to plants that only grow in upper elevation forests. The husband’s lie, combined with other evidence, led to his conviction for the murder.
