On a clear September morning in 2011, Deputy Cass Bollman sped east on an Iowa farm road, the bright sun glaring through the window of his patrol car. To the south was a Tetris puzzle of cornfields, the corn stretching over seven feet tall. Bollman had been about to take a coffee break at the Git ’N Go when the alert came over his radio for an incident out by 96th Street. South of here, walking westbound, there is an Asian male wearing a suit walking through a farm field. Nature of incident: suspicious.

Eighteen years in the Polk County Sheriff’s Office had taught Bollman to suspend judgment. Best-case scenario, he thought, the man in the field was an unusually well-dressed farmworker whom a neighbor had mistaken for an intruder. Worst-case scenario, the man was burying a body. What never crossed his mind was the story later claimed by the U.S. government: that the man was a critical player in America’s technological cold war with China, a foot soldier in what Secretary of State Mike Pompeo would call a “state-led set of economic practices that threaten the health of the American agriculture industry.”

A few miles outside the town of Bondurant, Bollman steered the car toward the corn, eventually slowing it to a stop in a clearing alongside a drainage ditch. In the distance, row upon row of stalks lined up like infantry, inbred corn lines that the owner of the land grew under contract with Monsanto. The company used the inbreds to produce genetically modified commercial hybrid seeds, which were then sold at great profit to farmers for the next year’s planting and eventually turned into food or fuel: perhaps ethanol, perhaps Doritos. Considering them valuable intellectual property, Monsanto kept the locations of its contract plots secret and enforced this secrecy through aggressive lawsuits.

Bollman’s colleagues had already arrived and were talking with the man in the field, so he got out to chat with the farmer who owned the land. The farmer had thought that the man’s clothes were suspicious, he explained, but it was his face that struck him first. Bondurant is 97% white. The man was not. It was the farmer who alerted the police.

As Bollman and the farmer stood alongside the field chatting, the gray SUV that had dropped the man off zoomed past. Bollman clambered back into his patrol car and flicked on his lights. The SUV pulled over to the side of the road about a quarter mile from the field.

The driver was Robert Mo, a scientist with two PhDs described on his driver’s license as Hailong Mo. He was 42 and lived with his wife and two children in Boca Raton, Florida. He had a shaved head and broad cheeks that tapered to an undefined jaw, and he wore small wire-rimmed glasses that gave him the look of a librarian. When Bollman asked him for identification, he was utterly polite.

Mo said that his companion was visiting from China, where he researched agronomy, and that they were driving across the Midwest looking at crops. A background check on the men came up clean, so Bollman let them off with a warning. “If you’re going to be on somebody’s property, you need to let them know,” he said as they drove away.

Later, the memory of the incident began to bug him. He filed a report, just in case, filling in the lines at the top of the form and leaving other identifiers blank: