At the beginning of a jury trial, a judge might request each side to turn in a list of prospective witnesses. The Criminal Procedure Law does not cover this, but case law in the area has developed somewhat.
The apparent purpose of the witness list is to inform prospective jurors of who will likely testify, thus allowing prospective jurors to state if they know any of the witnesses and would therefore possibly be partial. People v. Guzman, 176 AD2d 561, 575 NYS2d 26 (1st Dept 1991); Handling a Criminal Case in New York, 8:95 (199-2000 edition). Another result of submitting a witness list is to put the other side on notice of what witnesses will be called, and of possible defenses that may be asserted. Other side effects from this disclosure may occur as well.
There is arguably less of a problem with the prosecution being required to put forth its witness list at the time of jury selection. The prosecution is legally required to put on its case, and disclosure of those names is to be expected. (However, as with other discovery, disclosure of witness names can be subject to a protective order.) See, CPL sec. 240.70.
With the defense, though, there is no obligation to put on a case at all. Does requiring a witness list in any way impinge on this?
Also, for both sides, rebuttal and surrebuttal witnesses may be difficult to name, as each side does not know for sure who will be called by the other or what will be testified to.
If a side fails to include a name on the list but then calls that person as a witness, is that any ground for, e.g., precluding that witness from testifying? Certainly unexpected matters may come up when the other side puts on its case, and a party may feel the need to call a witness to answer, as it were, the unanticipated testimony. And, notice of defenses under CPL Article 250 has to be provided, in any event. (Note that where a witness violates a courtís sequestration order, the proper remedy is contempt, rather than denying the defendant the right to call the person as a witness.) See Richardson on Evidence, 6-205 (Farrell 11th edition).
In one case, defense counselís refusal to turn over a witness list at the beginning of trial was grounds for a finding of contempt. People v. Cangiano, 131 Misc2d 930, 502 NYS2d 349 (Sup Ct 1986).
One other downside of a witness list is its possible use at the close of the case. If a name is included on the list, or is mentioned on opening statement, but the person is not called, may an adverse inference be drawn? In one case, counselís inclusion of a name but failure to call that person resulted in a missing witness charge. Assuming the criteria for such a charge has been met. See Handling, 18:407, 18:409.
Where a person who is not listed is called as a witness, does the opposing party have any valid complaint? The opposing side could argue that they were unable to properly voir dire prospective jurors about attitudes towards a certain type of witness (e.g., informant, expert) or to find out if any prospective juror knew that person.
Where the court requires counsel to provide a witness list, it may be worthwhile to title it "Potential witnesses" or "Names to be mentioned." If the listís purpose is to ferret out bias, the involvement of any person, even one not called as a witness, could possibly affect the perception of a juror who knows that person.
By denominating the list in broader terms, the party may be able to better argue against a missing witness charge. List provided at end of trial: One last note about witness lists: a recent amendment to the CPL provides that, at the end of trial, the judge may, upon the juryís request, provide the jury with a list of all the witnesses who testified. CPL sec. 310.20(3) (L. 1999, ch. 66).