What did John Nichols do regarding this shark? What does this reveal about him?

John Nichols headed his own search for the sea monster, finally admitting that it was a great white shark he was hunting. Assisted by Robert Murphy, Nichols set out for Jamaica Bay on July 20th, armed with guns, knives and harpoons. Nichols soon spotted a shark a few boat lengths ahead. He was not convinced that a harpoon would bring down a huge shark. As they neared the creature, they saw that it was a harmless sand shark and held fire. The men continued their hunt but failed to track down a great white. This reveals Nichol's determination to now prove that it was a shark that had killed these people.