SPRINGFIELD — A Hadley man who authorities allege sold plutonium in 2023, and used hazardous black powder to ignite a fireball and detonate a dishwasher in his backyard during gatherings, has been indicted by a federal grand jury for allegedly possessing ammunition and explosives, after previously being convicted of a crime punishable by more than a year in prison.

Jacob D. Miller, 43, of 108 Hockanum Road, was indicted in U.S. District Court on one count of being a felon in possession of ammunition and one count of being a felon in possession of explosive materials, following his arrest on April 9 on a criminal complaint charging him with being a felon in possession of ammunition.

Miller remains in federal custody, with the court taking the matter of pretrial detention under advisement.

U.S. Attorney Leah B. Foley and James Crowley, acting special agent in charge of the FBI Boston Division, made the latest announcement on Tuesday.

On April 8, agents with the FBI, acting on a search warrant, found a box of about 50 rounds of Federal brand, American Eagle .45 auto, 230 grain ammunition in a bedside table in Miller’s home, and six firearms in a hallway safe. Explosive materials, hazardous chemicals and radioactive materials, including plutonium, were also located in the home.

Since 2002, the complaint alleges Miller has been obsessed with the unlawful possession of explosives, dangerous chemicals and radioactive substances. That year, during a search of Miller’s residence, blasting caps, bomb-making instructions, military equipment including an apparent rocket launcher, a homemade pipe bomb and a video depicting Miller igniting several improvised explosive devices, including one that he referred to as a “hand grenade,” were recovered. Miller was later convicted in state court of possessing those devices.

Then, while still on probation in 2014, the Massachusetts Radiation Control Program issued a cease-and-desist letter to Miller after discovering he was selling depleted uranium on eBay, though according to court records he responded by saying he was “only trying to make a quick profit with the sales.”

Despite Miller’s claims that he had ceased such activity, he allegedly launched his own online business called “Collect the Periodic Table” in 2017, through which he marketed and sold radioactive materials, including Plutonium-239 allegedly derived from Cold War-era Soviet smoke detectors.

Allegations also include Miller conducting at least five PayPal transactions for the sale of plutonium between June and October 2023. Additional records of plutonium sales were allegedly recovered from his residence during the recent searches.

Also in 2023, Miller allegedly directed an associate to purchase 5 pounds of hazardous black powder and have it shipped to his residence. Witnesses allegedly reported that Miller used the powder to ignite a fireball and detonate a dishwasher in his backyard during gatherings at his residence. During the April 2025 search, remnants of the shipment, including multiple bottles of explosive powder, one of which had been opened, were found.

According to court records, authorities cataloged and secured numerous other potentially hazardous substances found at Miller’s residence, including fuels, alkali metals, oxidizers, acids and toxic elements such as arsenic. The Massachusetts Department of Environmental Protection warned that these substances posed a serious risk to occupants, first responders and the public in the event of a fire, accident or natural disaster. MassDEP has since been ordered by the court to conduct a comprehensive safety evaluation and oversee the removal of hazardous materials from the residence.

That included nearly 200 chemicals, many of which were found hidden in a piano in the basement of Miller’s home. The complaint states that a potential pipe bomb labeled “Rubidium” was found in a cavity in the piano, along with numerous boxes of other chemicals.

According to the charging documents, on Feb. 9, 2004, Miller was convicted in Hampshire Superior Court in Northampton of one count of possession of child pornography and sentenced to seven years of probation. Miller also was convicted in a separate case in Hampshire Superior Court of two counts of possession of an explosive device and sentenced to 2½ years in jail and 10 years of probation. As a result of those convictions, Miller is prohibited under federal law from possessing ammunition, firearms and explosives.

The charges of being a felon in possession of ammunition and explosives each provide for a sentence of 15 years in prison, three years of supervised release and a fine of up to $250,000.

Hadley Police and State Police assisted, while Assistant U.S. Attorney Steven H. Breslow of the Springfield Branch Office is prosecuting the case.

Scott Merzbach can be reached at smerzbach@gazettenet.com.