Does a prosecutor have an ethical duty to disclose to the defense a witness who could help the defendant, and may a prosecutor tell a witness not to talk to the defense?
Apply this to your situation
This page answers the general question as of 1986. Ezel answers yours: whether it's allowed on your facts, under the current rules of professional conduct in your state, with citations.
Plain-English summary
Opinion E-86-7 addressed three questions about a public prosecutor who learns of a witness who may help the defendant. On the first, the committee concluded that although a prosecutor has no ethical duty to actively encourage a witness to talk with defense counsel or the defendant's investigator, the prosecutor has a duty under former SCR 20.37(2) to timely disclose to the defense the existence and whereabouts of the potential witness so the defendant has an opportunity to contact the witness. It added that it is unprofessional conduct for a prosecutor to discourage or obstruct communication between prospective witnesses and defense counsel or to advise any person to decline to give information to the defense, citing State v. Simmons and the prohibition under former SCR 20.43(2) against advising or causing persons to be unavailable as witnesses. The committee noted that these duties are subject to section 971.23, Wis. Stats., and the constitutional duty of disclosure (Brady v. Maryland), on which it did not comment.
On the second question, whether a prosecutor may write to a witness advising that the witness need not talk to the defense, the committee referred to its answer on the first question and noted, without opining, that a prosecutor communicating with a potential witness should inform the witness that there is no legal obligation to grant an interview but that it serves the interest of justice to cooperate.
On the third question, the committee concluded that no conflict of interest required a defense lawyer (Partner A) to withdraw from representing a criminal defendant after Partner B became city attorney, provided the city attorney is not involved in the prosecution, no city police officers are involved as witnesses, and the city attorney has no access to the file or communication with the prosecutor about the case. It cited its earlier Formal Opinions E-76-12 and E-81-3.
Currency note
This opinion was issued in 1986, before Wisconsin's July 1, 2007 adoption of the revised Rules of Professional Conduct for Attorneys (the state's Ethics 2000 update), and it analyzes conduct under the former Code. The prosecutor's special responsibilities are now addressed by Model Rule 3.8 and the duty not to obstruct access to evidence by Model Rule 3.4, while the conflict-of-interest question is governed by SCR 20:1.7 / Model Rule 1.7. Subsequent rule amendments or later opinions may have changed the analysis. Treat this page as historical context, not current guidance. Verify against current rules before relying on any specific rule, deadline, or requirement mentioned here.
Common questions
Q: Must a prosecutor tell the defense about a witness who could help the defendant?
A: The committee concluded that the prosecutor has a duty to timely disclose the existence and whereabouts of a known potential witness so the defendant can contact the witness, even though the prosecutor need not actively encourage the witness to cooperate with the defense.
Q: Can a prosecutor tell a witness not to talk to defense counsel?
A: No. The opinion treated it as unprofessional conduct for a prosecutor to discourage or obstruct communication between prospective witnesses and defense counsel or to advise any person to decline to give information to the defense.
Q: Must a defense lawyer withdraw when a law partner becomes city attorney?
A: The committee concluded withdrawal was not required, provided the city attorney is not involved in the prosecution, no city police officers are witnesses, and the city attorney has no access to the file or communication with the prosecutor about the case.
Background and rules framework
The opinion interpreted the former Code provisions governing a prosecutor's handling of witnesses (SCR 20.37(2) on disclosure and SCR 20.43(2) on not causing witnesses to be unavailable), concerns now reflected in Model Rule 3.8 (special responsibilities of a prosecutor) and Model Rule 3.4 (fairness to opposing party and counsel). The third question turned on conflict-of-interest principles now found in SCR 20:1.7 / Model Rule 1.7, applied where one partner prosecutes for a municipality while another defends a criminal matter the municipality touched.
Citations and references
Rules of Professional Conduct:
- Wis. SCR 20.37(2), 20.43(2) / Model Rule 3.8, Model Rule 3.4 (prosecutor duties on witnesses) (former Code provisions)
- Model Rule 1.7 (conflicts of interest)
Statutes:
- Wis. Stat. section 971.23 (criminal discovery)
Cases:
- State v. Simmons, 57 Wis. 2d 285, 203 N.W.2d 887 (1973)
- State v. Calhoun, 67 Wis. 2d 204, 226 N.W.2d 504 (1975)
- Brady v. Maryland, 373 U.S. 83 (1963)
- Disciplinary Proceedings Against Zapf, 126 Wis. 2d 123 (1985)
Other opinions cited:
- Wisconsin Formal Op. E-76-12
- Wisconsin Formal Op. E-81-3
See also
- WI Ethics Op. E-87-8: DA Communication With Represented Criminal Defendants
- WI Ethics Op. E-86-17: Disqualification of a Prosecutor Sued by the Defendant
- WI Ethics Op. E-86-14: City Attorney Prosecuting a City Employee
- WI Ethics Op. EF-11-02: Part-Time Prosecutor Conflicts
Source
- Landing page: https://www.wisbar.org/formembers/ethics/pages/formal-opinions.aspx
- Original PDF: https://www.wisbar.org/formembers/ethics/Ethics%20Opinions/E-86-7.pdf
Get today's answer for your situation
You just read a 1986 opinion on this question. Ezel checks the current rules of professional conduct in your state and answers your specific situation, with citations.
Opens in Ezel Pro. Every answer cites the rules it relies on.