oslo norwegian court sentence 17-year-old russian citizen nine months jail monday make small explosive device bring center oslo april prosecutors seek two-year sentence teenager say frequent islamist websites become radicalised possess image islamic state members kill prisonners teenager deny wrongdoing say plan detonate device forest near home device place central oslo busy saturday night april one day truck attack stockholm neighbor sweden kill five people oslo police bomb squad say device 30 cm ft across appear capable cause small amount damage l8n1hh0lt soon discovery device norwegian police raise country security threat level teenager live norway since 2010 previously apply asylum status application immediately clear 2011 far-right mass murderer anders behring breivik set car bomb oslo kill eight people destroy norway government headquarter go shoot rampage kill 69 people nearby utoeya island russian teenager hand jail sentence norway explosives case