U botanist aids police with plant expertise

Colleen Winters

When police investigating a murder in 1990 needed more evidence to solve the crime, they called University botanist Anita Cholewa.
“I’ve always been something of a Sherlock Holmes,” said Cholewa, a curator at the University’s Bell Museum of Natural History.
So when police found the murder weapons in the woodlands next to the victim’s property and couldn’t find fingerprints on them, they needed another way to prove the suspect had been there.
That’s when Cholewa found herself looking at the suspect’s pants under a microscope.
“His pants had gotten wet from the early morning moisture and had picked up bits and pieces of a branch,” she said. “The only place he could have picked these up was near her home.”
Cholewa’s testimony helped convict the suspect, and since then she’s been aiding investigators with her expertise in plant identification.
Although forensic botany is relatively new in the field of forensic science, Cholewa said helping the public identify plants is something she’s always done.
She said she receives calls dealing with everything from people curious about what kind of plant they found on a hiking trip to concerned workers at a poison control center wondering if the berries a small child ate were poisonous.
“One of the missions of the museum is to provide information, and to me this is a part of that,” she said.
Helping the public is also part of working at the University, Cholewa said. Her work in police investigations is one aspect of the outreach work she does and therefore is a public service.
Don Melander, a forensic scientist at the state Bureau of Criminal Apprehension, said the bureau calls on forensic botanists like Cholewa when vegetation is found on clothes, on other items from crime scenes or on suspects themselves.
“It’s not a high-use item,” he said, “but when you need it, it can be invaluable.”
Last year Cholewa helped convict a suspected child molester in Dakota County. The man had been baby-sitting and was accused of molesting the girl he was supposed to be watching, Cholewa said.
The girl, who had been eating blueberry pancakes, vomited on the suspect. Cholewa said she went to the crime lab to examine the suspect’s clothes and found blueberry seeds inside his jeans.
Not all cases require Cholewa to testify in court. “But when I do it’s kinda creepy because there is the suspect right in front of you,” she said. There is always some fear in the back of her mind, she said.
Cholewa is not the only Nancy Drew at the University. Valerie Cervenka, an entomologist who works for part of the extension service called Dial-U, has been doing forensic entomology as a private consultant for the past eight years.
Cervenka’s work differs a bit from Cholewa’s in that Cervenka deals with dead bodies, or more specifically, the insects found on dead bodies. In the past eight years, Cervenka said, she has studied bodies in 80 homicide cases.
“Forensic entomology is mainly used as corroborating evidence,” Cervenka said. In most cases, she said, entomology is used to determine when a person dies.
“When a body is decomposed, a medical examiner has fewer ways of determining the time of death,” she said. The type of insect found on a body is evidence just like any other type of evidence, she said.
Identifying evidence, whether plant or insect, and helping to solve crimes is rewarding, Cholewa and Cervenka said.
“It’s a fun part of what I do up here,” Cholewa said. “I’ve always kind of liked mysteries.”