An alleged leader in Japan’s Yakuza pleaded guilty on Wednesday to charges of attempting to traffic nuclear material sourced from war-ravaged Myanmar with the understanding that Iran would use it for a nuclear weapon.

Ebisawa was caught in a sting operation by the US Drug Enforcement Administration (DEA). Prosecutors say he boasted to one of the DEA’s sources and the source’s associate, who posed as an Iranian general, that he had access to uranium and weapons-grade plutonium, alongside drugs, from Myanmar.

In 2020, Ebisawa sent the DEA source a series of photographs depicting rocky substances with Geiger counters measuring radiation, as well as pages of what Ebisawa represented to be lab analyses indicating the presence of thorium and uranium in the substances. He continued communicating with the DEA sources in 2021 and 2022.

During the sting operation, including undercover agents, Thai authorities assisted US investigators in seizing two powdery yellow substances that the defendant described as "yellowcake".

The Department of Justice said a US laboratory determined that the isotope composition of the plutonium found in the samples was in fact weapons-grade, “meaning that the plutonium, if produced in sufficient quantities, would be suitable for use in a nuclear weapon”.