Isaac is a Defense protective services officer, a canine officer. He was at Fort Myer at the point of impact, dropping off his dog at the vet, and then he went down to the Pentagon and immediately began to assist in the rescue of people inside the building.
Isaac carried out probably eight individuals, and then when the smoke and fire became so dense that he couldn't enter the building, he used his voice, which is a deep baritone voice to call out "Follow my voice." He kept saying that over and over again and people heard that and were able to follow his voice to safety, probably another eight or ten individuals.
So we have the clothing that Isaac wore that day, his dog's collar, and his police shield from his dog, as well as a photograph of him taken by Richard Avedon, a well-known photographer in New York.