(July 11, 2019, 1:35 PM EDT) -- BALTIMORE — An FBI special agent can testify as an expert on prostitution for the government’s prosecution of a Maryland man on sex-trafficking charges because her opinions will help the jury understand the business of prostitution, a federal judge decided July 9 (United States v. Ryan Russell Parks, No. 1:18-cr-00317, D. Md., 2019 U.S. Dist. LEXIS 113550)....