One of the most important — and most misunderstood — rules at a criminal trial is Indiana Rule of Evidence 404. It controls whether a jury gets to hear about a person’s character, or about other acts they’ve committed, separate from the charge on trial. For a defendant, understanding this rule is critical to building a defense — and to knowing what risks come with certain trial strategies.
The General Rule: Character Evidence Is Usually Out
The starting point under Rule 404 is simple: evidence of a person’s character or character trait is not admissible to prove that they acted in accordance with that character on a particular occasion. In plain terms, the prosecution generally cannot argue, "this defendant is a violent person, so he probably committed this violent crime." Propensity evidence — using someone’s general character to suggest guilt — is exactly what the rule is designed to keep out.
The Defendant’s Exception
Here’s where it gets interesting for the defense specifically. Rule 404 carves out an exception that belongs to the defendant, not the State:
- A defendant may offer evidence of their own pertinent character trait. For example, a defendant charged with theft may be able to introduce evidence of their honesty. A defendant charged with a violent offense may introduce evidence of their peaceful character.
- If the defendant opens that door, the prosecutor may offer evidence to rebut it. This is the trade-off: putting character at issue lets the State respond with its own character evidence, which might not otherwise have been admissible.
- A defendant may also offer evidence of an alleged victim’s pertinent trait (subject to additional limits for sexual offense cases under Rule 412), and again, the prosecutor can offer rebuttal evidence.
- In a homicide case, if the defense argues the victim was the first aggressor, the prosecutor may introduce evidence of the victim’s peacefulness to rebut that claim.
This is a real strategic decision, not a formality. Introducing character evidence can help humanize a defendant or support a defense theory — but it also invites the prosecution to bring in character evidence of its own that might otherwise have stayed out of the trial entirely.
Prior Acts: Rule 404(b)
Separately, Rule 404 addresses evidence of other crimes, wrongs, or acts — commonly called "404(b) evidence." The rule is again a general prohibition: evidence of another act is not admissible to show that a person acted in character on the occasion at issue.
But this evidence can come in for other purposes if it’s relevant to something besides "this person has done bad things before, so they probably did it again." Recognized purposes include:
- Motive
- Opportunity
- Intent
- Preparation
- Plan
- Knowledge
- Identity
- Absence of mistake or lack of accident
If the prosecution wants to use this kind of evidence against a defendant, the rule requires advance notice — the prosecutor must give reasonable notice of the general nature of the evidence before trial (or, for good cause, during trial).
Why This Matters for the Defense
Rule 404 cuts both ways, and that’s exactly the point. It protects a defendant from being convicted because a jury thinks they’re simply a "bad person," while still giving the defense a path to present good character evidence if it helps the case. At the same time, it gives the prosecution a narrow, purpose-driven route to introduce prior acts — but only for something more specific than raw propensity, and only with notice.
Because these decisions carry real consequences either way, whether to open the character door — and how to respond to a 404(b) notice from the State — is one of the more consequential strategic calls made before and during trial.
This post is for general information and does not constitute legal advice. If you have questions about evidence in your case, contact our office to discuss your specific situation.