Detailed text transcripts for TV channel - CNN - 20170323:04:54:00
>> reporter: the attacker is able to stab an unarmed policeman before he is shot by responding officers. one photo from the scene is of a man on a gurney being treated for injuries. multiple knives strewn about the ground below him. it's unclear at this point who he is. a medical helicopter lands amid the chaos in new palace yard. authorities haven't confirmed to cnn who was airlifted out. but we do know tragically, the policeman died from his wounds. his name was keith palmer, a 15-year veteran. three others died in the attack. the assailant also dies from gunshot wounds. authorities almost i...