A defendant is on trial in federal court for the armed robbery of a casino. the defendant claims that he was out of town at the time of the robbery. the defendant calls an alibi witness to the stand to testify that she was with him on the trip. when asked where she was and who she was with on the date in question, the witness stated that she could not recall. she said she recalls spending a weekend at a bed and breakfast this spring, but she does not recall the date or her traveling companion. the defendant's attorney then showed the witness a letter written by her on stationery from the bed and breakfast, and asks her to look at it and try to answer the question again. the prosecution objects. how should the court proceed