What is Importance of having the presence of a third person?

As a general rule, third persons should not be present during the attorney’s interview with the defendant, particularly if the defendant will be discussing the facts concerning his or her alleged involvement in the offense. The presence of others may cause the defendant to feel ill at ease and be reluctant to honestly and openly discuss the case. More importantly, the presence of persons other than counsel and those persons engaged by counsel to aid in the defense may prevent the substance of communications made during the interview from being protected by the attorney-client privilege.