Facing a Criminal Sexual Conduct (CSC) charge in Minnesota is one of the most serious and intimidating legal situations a person can experience. What makes these cases even more challenging is that prosecutors can sometimes bring up “prior acts”—past behavior or allegations—to influence a jury’s perception of the defendant.
Even if those prior acts never led to charges or convictions, they can still be presented in court under specific rules. Knowing how and when prosecutors can use this evidence, and how defense attorneys fight to exclude or counter it, is critical in any CSC case.
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What Are “Prior Acts” in a Criminal Trial?
In criminal law, “prior acts” refer to evidence of previous behavior, conduct, or alleged offenses that are separate from the current charge.
Examples include:
- Previous accusations of sexual misconduct, even if they did not result in conviction.
- Past sexual contact or relationships with the same alleged victim.
- Other acts of violence, coercion, or manipulation.
- Testimony from individuals claiming prior, similar experiences with the defendant.
Ordinarily, criminal trials are supposed to focus only on the alleged incident at issue—not on the defendant’s general character or past conduct. But Minnesota law allows limited exceptions, especially in sexual assault cases.
The General Rule: Prior Acts Are Not Admissible
Under Minnesota Rule of Evidence 404(b), often called the “Spreigl rule,” evidence of other crimes, wrongs, or acts is not admissible to show that a person has a bad character or is likely to commit the same type of crime again.
In other words, prosecutors cannot argue:
“Because the defendant did this before, they probably did it again.”
This rule is based on fairness. Jurors might unfairly convict someone based on their past instead of focusing on the evidence in the current case.
However, there are exceptions that allow prior acts under certain circumstances.
The “Spreigl” Rule in Minnesota
The name “Spreigl evidence” comes from the Minnesota Supreme Court case State v. Spreigl, 272 Minn. 488 (1965).
In Spreigl, the court established that evidence of other bad acts may be admitted only for limited purposes, such as:
- To prove motive
- To show opportunity
- To establish intent
- To demonstrate preparation or plan
- To show knowledge or identity
- To rebut claims of accident or mistake
For example, if the defense argues that an encounter was accidental or misinterpreted, prosecutors may attempt to use prior similar acts to show intent or a pattern.
But before the evidence is allowed, prosecutors must meet a high standard.
How Spreigl Evidence Is Admitted
To introduce prior act evidence, prosecutors must follow strict procedures:
- Notice Requirement:
The state must notify the defense in writing before trial, detailing the prior incidents they plan to use. - Pretrial Hearing:
The judge holds a hearing to decide whether the evidence is admissible. - Judicial Balancing Test:
The judge weighs whether the evidence’s value outweighs its potential for unfair prejudice. - Limiting Instruction:
If admitted, the judge instructs the jury that they may only consider the evidence for limited purposes—not to decide guilt based on character.
This process is designed to protect defendants from being convicted simply because of past allegations.
How Prior Acts Apply in Sex Crime Cases
Minnesota law provides broader leeway for introducing prior acts in Criminal Sexual Conduct cases than in many other crimes.
This is due to a recognition that sexual assault often involves patterned behavior and that corroborating evidence can be rare. Courts therefore sometimes allow prior acts to show a pattern or common scheme—particularly under Minn. Stat. § 634.20.
Minn. Stat. § 634.20 – Relationship Evidence
Under Minn. Stat. § 634.20, prosecutors can introduce evidence of prior acts to show the “history of the relationship” between the defendant and the alleged victim.
This rule is often used in:
- Domestic assault cases, and
- Sexual assault cases involving ongoing or repeated contact between the same people.
The statute allows the state to show prior conduct—including threats, controlling behavior, or earlier sexual acts—to explain the dynamics of the relationship and to help the jury understand the context of the alleged offense.
For example:
- If the defendant and complainant were in a relationship, prosecutors may argue that past non-consensual encounters show a pattern of abuse.
- If the alleged victim delayed reporting, prior incidents may be used to explain fear or control.
However, this type of evidence is highly prejudicial and must still pass a judicial review to ensure fairness.
Other-Acts Evidence in Sex Offense Cases
Courts sometimes also allow “other-acts” evidence involving different victims if the alleged conduct is strikingly similar to the current charge.
This can include:
- Prior allegations of sexual contact with minors.
- Similar incidents where the defendant allegedly used a specific method, setting, or approach.
For example, if multiple people claim the defendant assaulted them in similar circumstances, prosecutors may argue that the pattern demonstrates a modus operandi—a specific, identifiable method of offending.
Defense attorneys often fight hard to keep such evidence out, because it can dramatically sway a jury even if it lacks solid proof.
The Danger of Prior Acts Evidence
Allowing prior acts in CSC trials can seriously prejudice the accused.
Jurors might subconsciously think:
“If they did something like this before, they must be guilty now.”
Even when judges issue instructions limiting how the jury can use the evidence, research shows that such evidence heavily influences verdicts.
In sexual assault cases, where emotions and social stigma are already high, the impact can be devastating.
That’s why experienced defense attorneys work aggressively to exclude or minimize the use of prior acts.
How Defense Lawyers Challenge Prior Acts Evidence
A skilled Minneapolis criminal defense attorney will use every available strategy to limit or exclude prior act evidence.
1. Contesting the Admissibility
The first step is to challenge whether the prior act meets the legal standard for admissibility under Rule 404(b) or § 634.20. The attorney can argue that the prior conduct is:
- Too dissimilar to the current allegation.
- Too remote in time.
- Unreliable or unproven.
- More prejudicial than probative.
2. Questioning Credibility of Prior Allegations
If prior allegations come from other individuals, the defense can challenge their credibility through cross-examination, showing inconsistencies or motives to fabricate.
3. Demanding a Pretrial Hearing
The defense can request a Spreigl hearing to ensure the judge fully evaluates whether the evidence is appropriate.
4. Limiting Jury Exposure
If evidence is admitted, the defense can request strict jury instructions clarifying that it cannot be used to prove guilt or bad character.
5. Offering Alternative Explanations
The defense can contextualize prior acts, showing they were misinterpreted, consensual, or unrelated to the alleged offense.
These steps are essential to prevent a jury from convicting based on reputation rather than facts.
Balancing Test: Prejudice vs. Probative Value
Under Rule 403, judges must balance probative value (the evidence’s relevance to proving a key fact) against unfair prejudice (its potential to mislead or inflame the jury).
Judges often consider:
- How similar the prior act is to the current allegation.
- How much time has passed.
- Whether the prior act was proven or merely alleged.
- Whether its value outweighs the risk of bias.
If the risk of unfair prejudice is too high, the evidence should be excluded.
Real-World Example
In State v. Kennedy (Minn. 2018), the Minnesota Supreme Court allowed prior acts evidence in a CSC trial because the alleged prior conduct closely mirrored the current charges.
However, in State v. Bolte (Minn. 2015), the Court reversed a conviction, finding that admitting prior allegations was more prejudicial than probative because the incidents were remote and uncorroborated.
These cases highlight the delicate balance courts must strike between fairness and context.
Why Prosecutors Rely on Prior Acts
Prosecutors often seek to use prior acts in CSC cases because:
- Physical evidence (like DNA) is often limited or absent.
- Many cases hinge on credibility—“he said, she said” situations.
- Prior acts can strengthen weak cases by painting a pattern.
However, this approach can unfairly shift the burden to the defendant, forcing them to explain unrelated past events instead of focusing on the current charge.
The Role of the Defense: Leveling the Field
An experienced Minnesota sex crimes lawyer plays a crucial role in ensuring fairness when prior acts are at issue. They can:
- File motions to exclude prejudicial evidence.
- Demand full disclosure and hearings under the Spreigl framework.
- Cross-examine witnesses about inconsistencies or ulterior motives.
- Emphasize the principle that every charge must stand on its own evidence.
These steps can often mean the difference between conviction and acquittal.
Key Takeaways
- Minnesota allows limited use of prior acts (“Spreigl” or relationship evidence) in CSC trials under Rule 404(b) and Minn. Stat. § 634.20.
- Prosecutors must give notice and obtain court approval before introducing this evidence.
- Judges must ensure the evidence’s probative value outweighs its prejudice.
- Prior acts are often used to show intent, pattern, or relationship, not to prove bad character.
- Defense attorneys can fight to exclude such evidence through motions, hearings, and cross-examination.
Because these rules are complex and their misuse can determine the outcome of a trial, having an experienced defense team is essential.
Contact Martine Law
Being accused of Criminal Sexual Conduct is overwhelming, especially when the state tries to use your past against you. But you have rights—and strong legal defenses are available.
At Martine Law, we understand how Minnesota courts handle prior act evidence and how to challenge it effectively. Our team defends clients with professionalism, compassion, and a relentless commitment to fairness.
If you are facing CSC charges or believe prosecutors may use prior allegations in your case, do not face it alone.
Contact us today for a confidential consultation with an experienced Minnesota criminal defense attorney.