Like millions of Americans, Andy Laurence is tormented by pollen grains emitted by grass, trees, and other plants. But to him those diminutive assailants, which under a microscope lens can resemble clusters of planets, aren’t merely triggers of seasonal sneezing attacks and itchy eyes.

What he sees are ubiquitous, natural wonders and tamperproof evidence that can help solve cold cases and identify corpses, or track suspected killers, smugglers, and drug dealers.

Laurence is part of a three-member U.S. Customs and Border Protection team of forensic palynologists who are using pollen analysis to help investigative agencies around the country go where conventional evidence hasn’t taken them.

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Pollen is a remarkable geographic locator. It sticks like glue to hair, clothing, and skin. Its tenacity and durability might be unrivaled. “Pollen is indestructible,” says Laurence. And for memory power, it would make generations of elephants envious. Pollen grains can date to 450 million years ago, he said.

His group, part of the Department of Homeland Security and based in Chicago, currently is working on about 20 cases. He declined to say whether any of them involve investigations in the Philadelphia region, saying he could not disclose details of active cases.

As far as he knows, his group, which also includes Shannon Ferguson and Katie Bailey and all of whom hold doctorates, is the only government team pursuing this work.

He would love to see the technique, which has been around for half a century, become more popular. He believes that it is grossly underutilized — particularly in the United States — and other palynologists say that’s wholly understandable.

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For one thing, this is highly specialized research. About 300,000 plants worldwide emit pollen, which essentially are their male sperm cells.

Palynology, the study of pollen grains and spores, isn’t for the short of attention span, and it doesn’t hurt to have a tapeworm-driven appetite for detail.

For those who master it, the oil industry is a favored landing place, but Laurence has chosen the investigative route. At least two of his investigations involved high-profile killings.

‘Baby Doe’

The clothing was no help in identifying the child — polka-dot pants, along with a zebra-striped blanket commonly sold at discount retailers throughout the Northeast.

The body of the girl was found by a jogger on June 25, 2015, on the Deer Island shore of Boston Harbor in a sealed black plastic trash bag, her face and fingerprints distorted by the water.

At one point, Philadelphia was in play as a venue of the crime. The U.S. Coast Guard said that based on wave action, the body could have come from hundreds of miles away.

The National Center for Missing & Exploited Children (NCMEC) solicited Laurence’s help.

Critical findings were the two types of cedar pollen found on the victim’s clothing. Cedar isn’t native to North America, and Laurence said only three arboretums in the Northeast hosted multiple species of cedars: the University of Pennsylvania’s Morris Arboretum in Chestnut Hill, the New York Botanical Gardens in New York City, and Arnold Arboretum in Boston.

Laurence finally matched one of the cedar pollen types to a tree that grew at the Boston arboretum. With the new evidence police questioned residents in the vicinity of the Arnold, one of whom said she had not seen a woman who lived in the neighborhood or her baby for weeks.

That led to the arrests of the mother, Rachaelle Bond, who pleaded guilty to being an accessory to the killing of 2-year-old Bella Bond. Her boyfriend, Michael McCarthy, was convicted of second-degree murder.

In a television interview in November, McCarthy denied involvement. He filed an appeal, which was denied on Monday.

Marcia King

The victim, evidently bludgeoned and strangled, was found in 1981 in southwestern Ohio by three men. It would take until April 2018 to figure out who she was.

Her body was fully clothed, save for shoes, wearing a “unique” buckskin jacket, according to investigators. Thus she became known as “the Buckskin Girl.” But neither the clothes nor anything else spoke to who she was, said Detective Lt. Steve Hickey, with the Miami County Sheriff’s Office, who took over the case in 2013.

As in the “Baby Doe” case, NCMEC suggested pollen analysis. “We didn’t know it existed,” said Hickey. The victim appeared to have been a hitchhiker, and he said, “We wanted to know the borders of where she traveled.”

In 2016, the Laurence team examined the pollen found on clothing and was able to say definitively she had been elsewhere.

They found evidence of pollen from oak forests in the Pittsburgh area, a good 250 miles away. They also found grains from the Western United States, indicating she had been there recently.

“Pollen was just the perfect test for us,” said Hickey. The findings gave the case fresh life and generated new rounds of publicity and exposure of a composite drawing.

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Ultimately, DNA analysis put a name to the face: Marcia King, 21, who had gone missing from her Arkansas home in 1980.

The case remains open.

‘Late in the game’

“The U.S.A. was kind of late in the game,” said Laurence, noting that pollen forensics has been more popular elsewhere, notably the United Kingdom, where Patricia Wiltshire, a pioneer in the field, has been involved in hundreds of cases in the last 25 years.

In this country, energy exploration appears to be more appealing to palynologists than forensics. The government estimates that half of the 1,000 palynologists in this country work in the petroleum industry: Pollen extracted from deep underground sediments during drilling operations can be quite useful in locating hydrocarbon deposits.

Laurence indicated that his allergies were unrelated to his interest in pollen. He was a trained archaeologist drawn to palynology by a professor at Texas A&M University.

No, he is not bothered by the pollen he examines. “It’s confined,” he said. “And we destroy it.”