what does "the department" here indicate?
Three messages from the Dallas police tapes indicate the range of chaos. At 1:56 P.M. the police radio had put out an incorrect home address for J. D. Tippit, who was a member of the department, and whose wife needed the commiseration of his brother officers. At 2:24 a dispatcher broadcast, "A Mr. Bill Moyers is on his way to swear in Mr. Johnson; correcting himself at 2:35, he told cruisers, "We now have information that Judge Sarah Hughes is en route from Parkland to Love to swear President Johnson in." Moyers was ineligible to preside over the induction of a notary public, and Sarah wasn't near the hospital. At the same time, both errors are understandable.】
Tippit is the secret service agent killed by Oswald. I think he should be a member of FBI, then , what does this "department"mean? which department is he belonged to?