chapter IV

, the building was probably first sealed off no earlier than 12:37 by Inspector Herbert Sawyer.[C6-81] The shortest estimate of the time taken to seal off the building comes from Police Officer W. E. Barnett, one of the officers assigned to the corner of Elm and Houston Streets for the Presidential motorcade, who estimated that approximately 3 minutes elapsed between the time he heard the last of the shots and the time he started guarding the front door.[C6-82] According to Barnett, “there were people going in and out” during this period.[C6-83] The evidence discussed in