Principle 2: Thorough Investigation edges that interviews are “but one method of ascertaining the facts.”167 Not all countries conduct personal interviews in the course of their election investigations. In Mexico, for example, oral testimony carries little weight in terms of the standard of evidence; consequently, investigators can only gather written testimony and can even face charges of harassment for conducting an oral interview.168 However, since interviews can serve as a valuable investigative tool, most states give investigators the discretion to interview. In the United Kingdom, the Electoral Commission encourages police officers investigating electoral offenses to “invite” relevant parties for an interview.169 In a recent report on an political finance investigation, the U.K. Electoral Commission noted that all interviews were voluntary but the one person who declined sent a written response.170 In South Africa, the Election Commission may afford interested parties the opportunity to make additional “oral submissions” when investigating objections to election results.171 Likewise, Indonesia allows investigators to decide whether or not to interview: “In the process of investigating the Report of Suspected Violation, Election Supervisor may summon the Report Submitter, the reported, the party suspected to perpetrate the violation, witnesses, and/or experts to provide their testimony and/ or clarification under oath.”172 As the Indonesian law highlights, there are different categories of potential interviewees. These include the complainant (the individual alleging an election violation), the suspect or subject (the individual accused of an election violation), and witnesses (any other individuals who “may have 167 Comm’r of Canada Elections, Ch. 11 Interview Techniques, in Investigators’ Manual 1 (2000) [hereinafter Canadian Investigators’ Manual Ch. 11]. 168 Chad Vickery & Erica Shein, IFES, Mexico Elections 2012: An Assessment of the Investigation and Adjudication of Election Complaints 22 (July 2012) (unpublished report) (on file with IFES); Email from Mexican Legal Specialist, Democracy Building International (Jun. 26, 2013, 12:28 EST) (on file with IFES). 169 Electoral Comm’n, Guidance on Preventing and Detecting Electoral Malpractice 32 (2013) (U.K.). 170 Electoral Comm’n, Investigation: UK Independence Party (UKIP) (2018), https://www.electoralcommission.org.uk/ our-work/roles-and-responsibilities/our-role-as-regulator-of-political-party-finances/sanctions/report-on-an-investigation-into-the-uk-independence-party-ukip. 171 Election Regulations of 2004, GN R12 in GG 25894, ¶ 31(2) (Jan. 7, 2004) (S. Afr.). 172 Bawaslu Regulation Concerning the Procedure of Reporting and Handling of Violations in the Elections of Members of the People’s House of Representatives, House of Regional Representatives, and Regional People’s House of Representatives, Law No. 14/2012 (2012), art. 15(1) (unofficial IFES translation) [hereinafter Bawaslu Regulation No. 14/2012] (emphasis added). 69