House Office of Congressional Ethics: History, Authority, and Procedures [Updated March 28, 2019] [open pdf - 1MB]
From the Document: "The House Office of Congressional Ethics (OCE) was established on March 11, 2008, with the passage of H.Res. 895. It was most recently reauthorized by the House as part of the rules package (H.Res. 6) adopted by the 116th Congress on January 3, 2019. The office's establishment followed years of efforts by groups within and outside Congress to create an independent entity to investigate allegations of misconduct by Members, officers, and employees of Congress. During the 110th Congress (2007-2008), Speaker of the House Nancy Pelosi and Minority Leader John Boehner created the bipartisan Special Task Force on Ethics Enforcement, chaired by Representative Michael Capuano, to consider whether the House should create an 'outside' ethics-enforcement entity. The task force worked for nearly a year before issuing its recommendations for the creation of the OCE."
CRS Report for Congress, R40760
Congressional Research Service: https://crsreports.congress.gov/