year. he talked about feeling uncomfortable showing his muslim faith on campus. his mother says he never spoke about that. he was a good kid. the only thing he complained about was grades at the university. he was born in somalia and came to the united states in 2014 as a legal permanent resident. investigators still determining the why. john and christine. >> pamela, thank you. a senior official in the obama administration tells cnn the attacker went through the most strict screening possible before granted a green card. this process took more than two years. in addition to a face-to-physiciface-to-face interview, they were cross-checked against ougall u. databases. if the attacker was radicalized, investigators believe it happened after he arrived in the united states. president-elect trump