Administering an oath to a taxpayer is an underutilized tool for an agent. The oath is very effective when interviewing third parties, subordinate employees, etc. Also, if a taxpayer has previously given inaccurate or misleading testimony, the same questions should be asked again under oath. The oath should not always be used at the start of an interview. It should be used at the first sign of a misstatement.
http://www.irs.gov/pub/irs-tege/eotopicf97.pdf
When the oath is administered, the
person taking it should be asked to stand and raise his or her right hand. The oath should be given as follows:
"
Do you solemnly swear (affirm) under the penalties of perjury that the testimony you are about to give in this matter is true and correct to the best of your knowledge and belief
so help you God?"
As noted, the term "affirm" may be substituted.
The phrase "so help you God" may be omitted.
The witness should respond by saying "I do." See IRM 4022.41(3). However, a witness cannot be forced to give testimony under oath. Where a witness refuses to take the oath, a memorandum should be prepared to document the fact that the witness refused to take the oath.
4. Authority