The suspect, identified only as Jurgen K., was detained last week by Poland’s Internal Security Agency (ABW), according to Stanisław Żaryn, spokesman for the country’s security services chief.
The detained man has since been charged by prosecutors with illegal possession of explosives and ammunition and remanded in custody for three months following a court order, Żaryn said.
While searching the place where the detained man worked and resided in Poland’s north-central Kujawsko-Pomorskie province, investigators, aided by bomb disposal experts, found "explosives – 1.2 kilograms of TNT, both liquid and pressed – as well as ammunition, a detonator, a tear gas grenade and electronic storage devices," Żaryn said, as quoted on the gov.pl website.
The suspect voiced "radical, anti-systemic views," mainly through social media, and supported "extreme right-wing organizations,” according to Żaryn’s statement.
The organized crime group of which the detained man is believed to have been part "has operated on the territory of Poland and other countries," the statement said.
The investigation is ongoing, with further arrests possible, according to Żaryn.