Secret Service Agents Called Away before JFK Shot
A remarkable video. It shows the two Secret Service agents whose locations were the most important being called away, obviously to the consternation of the one on the right. The one on the left cannot be seen very well. President Kennedy was fatally shot a short time later.
Many in Dallas despised Kennedy and his policies. This had been publicized nationally in the days and weeks prior to his arrival. An ugly incident involving him was considered highly likely. Under such conditions it would be expected that the Secret Service would be especially alert.

