Criminal Discovery in Minnesota: What the Prosecution Must Share

Minnesota's "Open File" Rule

Under Rule 9 of the Minnesota Rules of Criminal Procedure, in felony and gross misdemeanor cases the prosecutor must — on the defense's request and before the Omnibus Hearing — allow access to all matters within the prosecutor's possession or control that relate to the case, except for narrow protected categories. The aim is broad, early discovery between the parties without needing to involve the judge for routine matters.

What the Prosecution Must Disclose

Witnesses

The names and addresses of people the state may call at trial, along with their prior conviction records within the prosecutor's actual knowledge, and any written or recorded statements (and summaries of oral statements). The state must also identify others who have information relating to the case. One nuance: the prosecution generally need not name a rebuttal witness before trial.

Your Own Statements

You're entitled to copies of your own statements within a reasonable time. If a statement was recorded by audio or video, you may not automatically get the actual recording, but it must be made available for your lawyer to review.

Documents and Physical Evidence

Books, papers, documents, photographs, police reports, tangible objects, relevant locations, and grand jury transcripts — your lawyer can inspect and copy these.

Test Results and Expert Opinions

Reports of physical or mental examinations and scientific tests that relate to the case, plus a right to have reasonable independent testing done. If a test might use up the evidence (preventing further testing), the prosecutor must give notice and a chance for your expert to observe. Experts who didn't write a report still must provide a written summary of their expected testimony, opinions, and the basis for them.

This area has real teeth in practice. For DNA, access to the data, methodology, and results is critical so an independent expert can review the work. And Minnesota courts have held that, on a proper showing, the prosecution may have to produce the source code for testing machines like the Intoxilyzer used in DWI cases.

Criminal Records

The prosecutor must disclose known prior convictions of the defendant and of defense witnesses (once the defense identifies them). Juvenile adjudications generally aren't covered by a routine pretrial witness-list request.

Exculpatory Evidence: The Brady Rule

This is the most important protection in all of discovery. Under Brady v. Maryland, a foundational U.S. Supreme Court case, the prosecution must disclose evidence favorable to the accused — evidence that tends to negate guilt or reduce punishment — and must do so regardless of whether the prosecutor is acting in good or bad faith. In Minnesota, the prosecutor has a constitutional duty to volunteer this material, not just respond to requests.

Two key extensions:

• Impeachment evidence counts. Under Giglio v. United States, evidence that undermines a state witness's credibility — like a plea deal or promise of leniency given to a cooperating witness — must be disclosed.
• The duty reaches the whole prosecution team. It extends to material held by police and others who investigated or evaluated the case, not just what's physically in the prosecutor's own file. Evidence can't be hidden by keeping it in another agency's hands.

What this means for you: If the state is sitting on something that helps you — a witness who points elsewhere, a deal with an informant, a lab result that doesn't fit — it must come out. Failure to disclose favorable, material evidence can be grounds to challenge a conviction.

When Evidence Is Lost or Destroyed

Sometimes evidence is contaminated, lost, or destroyed. The general federal rule is that the police's failure to preserve "potentially useful" evidence is not a due-process violation unless the defendant shows bad faith. But the nature of the evidence, the reasons for its loss, and the resulting prejudice all matter to what remedy a court will order, and Minnesota courts can apply a stricter standard.

Evidence That Requires a Court Order

Most discovery happens automatically, but some materials require a motion and judicial review:

• Materials held by other government agencies — on a good-cause motion, the court can order the prosecutor to help the defense get access to case-related materials held by agencies outside the prosecutor's control.
• Other relevant material — the court can order disclosure of additional material on a showing that it "may relate to the guilt or innocence of the defendant or negate guilt or reduce culpability."

Limits on Discovery (Rule 9.03)

Discovery is broad but not unlimited. The court can regulate it:

• Protective orders — on a showing of good cause, the court can restrict, defer, or condition disclosures. Discovery isn't a "fishing expedition."
• In camera review — a judge can review disputed material privately, with the record sealed for any appeal.
• Excision — when only part of a document is discoverable, the rest can be withheld and sealed.
• No impeding investigations — neither side may tell witnesses (other than the defendant) to refuse to talk to opposing counsel.
• Custody and use — materials shared in discovery must stay in counsel's custody and be used only for the case.

Key Terms

• Discovery: The pretrial exchange of evidence between prosecution and defense.
• Brady material: Favorable evidence the prosecution must disclose to the defense.
• Giglio / impeachment evidence: Evidence undermining a state witness's credibility, including deals for testimony.
• Omnibus Hearing: The pretrial hearing by which discovery is generally to be completed.
• Protective order: A court order limiting or conditioning disclosure.