weapon of mass destruction and his arrest a culmination of under a cover sting that started over a year ago and details are still unraveling tonight, casey steegel following the story from our los angeles newsroom. what are we learning from the justice department? >> reporter: well, according to all of the affidavits, the teen told police that he was planning, quote, a spectacular fireworks show, and, one that would leave the spectators either dead or injured. and, what is more, that 19-year-old telling the feds, that he had been thinking about carrying out a violent jihad since he was just 15 years old. here's what we know about the suspect. mohammed asman mohammed, born in somalia, a naturalized citizen of the u.s. and, a student at oregon state university. his father apparently works in portland and his stepmother lives in minneapolis, and the feds say mohammed had been in regular e-mail contact with an associate in northwest pakistan,