A man in Massachusetts has pleaded guilty to charges of importing and selling plutonium obtained from Russia and mailing the material, as well as other toxic hazardous substances, to customers in the United States and abroad, federal prosecutors said.

The man, Jacob D. Miller, 44, had been charged last year with importing nuclear material without lawful authority, mailing hazardous materials and possessing child pornography, the U.S. Attorney’s Office for the District of Massachusetts said in a statement.

Also, because Miller had previous felony convictions, he faced charges for possessing ammunition and explosive materials, the prosecutors said.

Miller agreed to the plea in September, the documents show. Because he had earlier felony convictions, the nuclear material count and the child pornography charge could each lead to a sentence of up to 20 years in prison. U.S. District Court Judge Mark G. Mastroianni scheduled a sentencing hearing Jan. 21, 2027.

Miller’s lawyer, Charles Dolan, could not be reached for comment Tuesday.

On April 8, 2025, authorities conducted a search warrant at Miller’s home in South Hadley. They found ammunition, six firearms, explosive materials, hazardous chemicals, plutonium and child sexual abuse materials, the filing said. Miller has been in federal custody since his arrest April 9, 2025.

He was indicted by a grand jury April 17, 2025, court documents show. Prosecutors alleged at that time that Miller had a “long-standing and unlawful obsession with explosives, dangerous chemicals, and radioactive substances.”

According to prosecutors, Miller had state convictions in Massachusetts in 2004. He was sentenced to seven years of probation for possessing child pornography, and 1 1/2 years in prison and 10 years of probation for possessing an explosive device.

In 2017, he started a business called “Collect the Periodic Table,” from his home, prosecutors said.

It advertised the sale of “every collectible element sample and even some rare and hard to find ones,” including what it called a sample from a “cold war era smoke detector source” for $500, the document said. The sales included plutonium-239, a toxic radioactive material, that he imported from a seller in St. Petersburg, Russia, it said.

Plutonium-239, an isotope of plutonium, can be used as a fissile material for nuclear energy reactors and weapons. But doing so requires significant quantities of purified material. Authorities did not say how much plutonium Miller had acquired.

From Dec. 30, 2020, through March 31, 2025, he sold the substance through the mail to at least 67 customers in the United States, Canada, Japan and Switzerland.

He also sold thallium, a highly toxic metallic element, prosecutors said, to 71 customers.

On April 5, 2025, PayPal records show that Miller sold two 5-gram units of thallium to a man named Stuart Hanmer in Minnesota, who provided a “lethal amount” of thallium to his roommate, the court document said.

Hanmer, who also purchased thallium from other sources, was indicted last October for the murder of his roommate, authorities in Minnesota said in a statement.

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This article originally appeared in The New York Times.

By Christine Hauser/US Attorney’s Office
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