U.S. Secret Service: Investigative Operations Confer Benefits, but Additional Actions Are Needed to Prioritize Resources, Report to the Committee on Homeland Security and Governmental Affairs, U.S. Senate [open pdf - 4MB]
From the GAO [Government Accountability Office] Highlights: "Commonly known for protecting the President, the Secret Service also investigates financial and electronic crimes (e.g., counterfeit currency and identity theft). In recent years, Congress and a panel of experts established by the Secretary of Homeland Security have raised concerns that the Secret Service's investigative operations may negatively affect its protective operations. [...] This report examines, among other things, the extent to which the Secret Service's (1) investigative operations support or negatively affect its protective operations; (2) Office of Investigations has developed a plan to combat its priority criminal threats; and (3) staffing model accounts for federal employee compensation limits. GAO analyzed Secret Service data related to investigation and protection activities from 2014 through 2018; conducted semi-structured interviews with current and former special agents and federal prosecutors; and reviewed Secret Service policies and guidance."
Government Accountability Office: http://www.gao.gov/