keith martin took a different direction out. the guy points a gun at him and says get out of my way. i'll kill you too. roader was driving out. they were next to each other. he threw a cup of coffee at him. roader then left. >> around 1:30 in the afternoon, johnson county deputies take it upon themselves to watch interstate 35, which is the main road that comes into kansas city, and we're watching for the tag that we broadcast. >> they pulled him over. >> step out of vehicle, and face away from me. >> they get him out of car. put his hands behind his back to lay down. they go down there. they cuff him, and he's in custody. >> reporter: it's no mystery who pulled the trigger, but authorities work to track down any known associates of roader's to learn whether others were involved. >> we had talked to his ex-employers, we talked to friends. we talked to members of his bible studies. we talked to his family. he did this very secretive. >> reporter: three days after the shooting, scott meets with his defense team. >> we told scott p