the witness says i did not see a weapon on him. could he have been casing, reviewing? >> more than likely he was. >> now, the man also said he believes he had seen him before. that is a little inconsistent with information coming out from investigators, because he wasn't scheduled to start work yet, though he did have clearance. he did have the ability to go inside and you're saying that may have been skin the with preparation? >> right, yes. he absolutely would have probably walked through this. he walked through it in his mind and physically to know that it would happen the way that he wanted it to happen. >> what we understand about the configuration of the building. a large atrium hallway, that the shooter reportedly found a high vantage point. you're saying that makes sense strategically? >> absolutely. he would have wanted to make sure he accomplished his mission which led him on what he would have felt was a killing journey. that was the objective of his