McDonald ordered the man to his feet and heard him say, “Well, it’s all over now.” The man drew a gun from his waist with one hand and struck the officer with the other. McDonald struck out with his right hand and grabbed the gun with his left hand. After a brief struggle McDonald and several other police officers disarmed and handcuffed the suspect and drove him to police headquarters, arriving at approximately 2 p.m. Following the assassination, police cars had rushed to the Texas School Book Depository in response to the many radio messages reporting that the shots had been fired from the Depository Building. Inspector J. Herbert Sawyer of the Dallas Police Department arrived at the scene shortly after hearing the first of these police radio messages at 12:34 p.m. Some of the officers who had been assigned to the area of Elm and Houston Streets for the motorcade were talking to witnesses and watching the building when Sawyer arrived. Sawyer entered the building and rode a passenger elevator to the fourth floor, which was the top floor for this elevator. He conducted a quick search, returned to the main floor and, between approximately 12:37 and 12:40 p.m., ordered that no one be permitted to leave the building. Shortly before 1 p.m. Capt. J. Will Fritz, chief of the homicide and robbery bureau of the Dallas Police Department, arrived to take charge of the investigation. Searching the sixth floor, Deputy Sheriff Luke Mooney noticed a pile of cartons in the southeast corner. He squeezed through the boxes and realized immediately that he had discovered the point from which the shots had been fired. On the floor were three empty cartridge cases. A carton had apparently been placed on the floor at the side of the window so that a person sitting on the carton could look down Elm Street toward the overpass and scarcely be noticed from the outside. Between this carton and the half-open window were three additional cartons arranged at such an angle that a rifle resting on the top carton would be aimed directly at the motorcade as it moved away from the building. The high stack of boxes, which first attracted Mooney’s attention, effectively screened a person at the window from the view of anyone else on the floor.