A Hadley man has been indicted by a federal grand jury in Springfield for allegedly possessing ammunition and explosives despite previously being convicted of a felony, prosecutors said.

SPRINGFIELD — While Hadley resident Jacob D. Miller sits in custody awaiting a ruling on his pretrial release, a Western Massachusetts grand jury has indicted him on two criminal charges.

This, as he found out, isn’t something you should do lightly, as the one he used ended up containing an interesting mix of radioactive materials, including small amounts of plutonium-239 ...

Beginning in the late 1950s, the U.S. met this challenge by developing nuclear batteries known as radioisotope thermoelectric generators (RTGs) and producing plutonium-238 (Pu-238) as their fuel, ...

But Miller’s alleged possession of highly radioactive plutonium did not capture the attention of federal agents at high levels, according to court records. A federal investigator told local ...