The HSCA determined that
- President Kennedy first showed a reaction to a "severe external stimulus" by Zapruder frame 207;
- Governor Connally first showed a reaction to a "severe external stimulus" by Zapruder frame 224;
- at least two shots, spaced approximately 6 seconds apart, were fired at the Presidential limousine.
QUOTE:
The first, missed shot.
The first reaction by any of the limousine occupants to a severe external stimulus begins to occur in the vicinity of Zapruder frames 162-167. At this time, Connally is looking to his left, when his head begins a rapid, sudden motion to the right. In quantitative terms, he turns his head approximately 60° to his right in one-ninth of a second (a rate equivalent to a 540° rotation per second). He pauses momentarily and then executes a further 30° turn to his right, within an eighteenth of a second (again, a rate equivalent to a 540° rotation per second). This initial rapid motion, in which Connally has apparently turned his head to look behind him, is accompanied during the next approximately 20 frames by a more gradual 60° shift to the right of his upper torso. Although it is apparent that none of the limousine occupants has been shot at the time that Connally initiates this movement, the Panel considers these actions to be particularly significant because they were consistent with his Warren Commission testimony that he turned in response to having heard the first shot and was struck almost immediately afterwards.
During the period of Connally's initial rapid movement, however, no one else shows a comparable reaction. The President does not appear to react to anything unusual prior to Zapruder frame 190. The Panel observed, however, that at approximately this time, a young girl who had been running across the grass, beyond the far curb of the street where the limousine was traveling, suddenly began to stop and turn sharply to her right, looking up the street in a direction behind the limousine.
The second shot.
At approximately Zapruder frame 200, Kennedy's movements suddenly freeze; his right hand abruptly stops in the midst of a waving motion and his head moves rapidly from right to his left in the direction of his wife. Based on these movements, it appears that by the time the President goes behind the sign at frame 207 he is evidencing some kind of reaction to a severe external stimulus. By the time he emerges from behind the sign at Zapruder frame 225, the President makes a clutching motion with his hands toward his neck, indicating clearly that he has been shot. Connally's movements as he emerges from behind the sign at Zapruder frames 222-224 also indicate that he is reacting to a severe external stimulus. He appears to be frowning, and there is a distinct, stiffening of his shoulders and upper trunk. Then there is a radical change in his facial expression, and rapid changes begin to occur in the orientation of his head.
The third shot.
At frame 313, approximately 6 seconds (based on the 18.3 frames per second exposure rate of the Zapruder camera) after the President disappears behind the sign, his head is seen exploding from the impact of a bullet.
Source HSCA report volume 6 page 17 & 18.
