Polish police said they arrested a 20-year-old man Thursday who made explosive devices using store-bought ingredients, days after a bomb killed eight people in Norway. Police seized several substances from a makeshift laboratory at the man\'s home in Muszyna in the south of the country, including two assembled devices they said were \"quite powerful\". \"The man, drawing from sources of information accessible to all, mixed different explosive substances and tested their reaction,\" said a statement from police in Krakow. He filmed his experiments and explosions. One of the films, posted on the Internet, allowed police to identify the man. \"He is someone who is passionate about home-made explosives. It is a dangerous hobby, but it seems that there is no ideology behind it,\" Krakow police spokesman Michal Kedzior told AFP. The man risks eight years in jail for \"threatening the lives and health of others,\" under the Polish penal code. Anders Behring Breivik, who claimed responsibility for twin bomb and shooting attacks that killed 76 people in Norway last Friday, had ordered chemical substances from a Polish firm that can be used in bomb-making. Polish prosecutors are investigating whether the firm committed an offence by selling him the chemicals.