Calling the reports "shocking and unacceptable," U.S. Reps. Charlie Crist and Kathy Castor have fired off a letter to Interior Secretary Ryan Zinke Monday, demanding a full investigation into allegations that ZooTampa’s senior veterinarian harmed manatees with improper medical procedures.The U.S. Fish and Wildlife Service, which reports to Zinke, last month sent a letter to officials of what was formerly known as the Lowry Park Zoo regarding "credible reports" accusing the veterinarian, Ray Ball, of manatee malpractice. It outlined allegations of improper feeding, unorthodox drug use, field amputations that left animals with protruding bones and, in two cases, the accidental deaths of manatees.The agency has given the zoo until Dec. 7 to respond to those reports, and warned that until then Ball is not to touch any manatees needing care. "We applaud (the agency) for taking this first step," Crist and Castor wrote in their letter.The agency also warned that Ball’s activities could pose a threat to the zoo’s license to handle manatees.In response, zoo CEO Joseph A. Couceiro announced Friday that Ball, who also serves as the zoo’s vice president of medical sciences, will "be on paid administrative leave while we review veterinary care procedures and gather the information needed."INVESTIGATION: Vet for Tampa zoo accused of killing manatees through malpractice. Vice president Larry Killmar said last week that the zoo would assemble a team of manatee experts and veterinarians to review Ball’s actions in hopes of answering the federal agency’s questions.A former employee of the zoo said she and other employees had complained about Ball to the zoo’s management, to no avail. As a result, Crist and Castor, both Democrats, urged the Interior Department to open "a full investigation into the conduct of Dr. Ball and ZooTampa." "We respect their call for a review," zoo spokeswoman Kristy Chase-Tozer said. In another development, she said an inspector for the U.S. Department of Agriculture had visited the zoo at their invitation and "conducted a thorough site inspection of the manatee care facility. He found no issues to report."The original notification from Fish and Wildlife outlined four lines of inquiry.The first involves a treatment called "chest taps." When manatees are hit by boats, their ribs can break and puncture a lung so they are unable to submerge. A chest tap involves sticking a needle into the manatee’s chest to remove the air and determine the size of the puncture. But the needle can go in too deep and puncture the lung again."After chest taps were performed by Dr. Ball," the federal agency’s letter said, "two manatees died, and the necropsy reports showed perforations in the lungs from chest taps."The second item involves the rescue of wild manatees that had become entangled in fishing line."On more than one occasion," the letter states, "Dr. Ball performed in-field amputations of manatees’ flippers, at times without treatment for infection and pain, and at times releasing the manatees with exposed bones."The third point looked at "experimental drugs and/or experimental methods of administering drugs" that Ball used on injured or ailing manatees.The final point, the letter said, concerned Ball’s practice of feeding hay to young or injured manatees. Hay offers no nutritional value to manatees, but it tends to be cheap.Senior news researcher Caryn Baird contributed to this story. Contact Craig Pittman at [email protected] Follow @craigtimes.