Please answer the following question: Given the following context:  Another letter to The New York Times blamed the shark infestation on the maneuvers of German U-boats near America's East Coast. The anonymous writer claimed, "These sharks may have devoured human bodies in the waters of the German war zone and followed liners to this coast, or even followed the Deutschland herself, expecting the usual toll of drowning men, women, and children." The writer concluded, "This would account for their boldness and their craving for human flesh."Decades later, there is no consensus among researchers over Murphy and Lucas's investigation and findings. Richard G. Fernicola published two studies of the event, and notes that "there are many theories behind the New Jersey attacks," and all are inconclusive. Researchers such as Thomas Helm, Harold W. McCormick, Thomas B. Allen, William Young, Jean Campbell Butler, and Michael Capuzzo generally agree with Murphy and Lucas. However, the National Geographic Society reported in 2002 that "some experts are suggesting that the great white may not in fact be responsible for many of the attacks pinned on the species. These people say the real culprit behind many of the reported incidents—including the famous 1916 shark attacks in New Jersey that may have served as inspiration for Jaws—may be the lesser known bull shark."Biologists George A. Llano and Richard Ellis suggest that a bull shark could have been responsible for the fatal Jersey Shore attacks. Bull sharks swim from the ocean into freshwater rivers and streams and have attacked people around the world. In his book Sharks: Attacks on Man (1975), Llano writes, One of the most surprising aspects of the Matawan Creek attacks was the distance from the open sea. Elsewhere in the book are accounts of well-documented shark-human interactions at Ahwaz, Iran, which is 90 miles (140 km) upriver from the sea. It may also be of interest to note that sharks live in Lake Nicaragua, a fresh-water body, and in 1944 there was a bounty offered for dead freshwater sharks, as they had "killed and severely...  answer the following question:  What had "killed and severely injured lake bathers recently?"
A:
freshwater sharks