It is an old maxim of barristers that you should not ask a witness a question in court to which you do not already know the answer. We are also told that we are our own worst lawyers. Both principles proved to be very true in the following record of a U.S. criminal case, much to the loss of the accused:

United States Court of Appeals District of
Columbia Circuit.

Joseph NANCE, Appellant,
UNITED STATES of America, Appellee.

Defendant was convicted of robbery. From the judgment of the United States District Court for the District of Columbia, Edward A. Tamm, J., the defendant appealed. The Court of Appeals, Bastian, Circuit Judge, held that evidence that the accused
asked a witness at the preliminary hearing how the witness knew it was the accused when he had a handkerchief over his face was properly admitted at the trial as an admission, since there was no compulsion to ask the question, even though the accused was not a lawyer and may have been in unfamiliar surroundings, and that the evidence sustained the conviction.

Evidence that at preliminary hearing accused asked witness “How do you know it was me when I had a handkerchief over my face?” was properly admitted at trial for robbery as evidence and an admission of guilt.

299 F.2d 122, 112 U.S.App.D.C. 38