Texts, photos, call logs, and video can be used in a Montana partner or family member assault (PFMA) case by either side, as long as the party offering them can show they are genuine and the content is otherwise admissible. The same rules let the other side challenge evidence that is partial, undated, or edited. The single most important practical rule is to preserve everything exactly as it is. This page is part of our Montana Domestic Violence Guide.
The Rules That Govern Digital Evidence
Montana has no separate rulebook for phones. The Montana Rules of Evidence apply, and four of them do most of the work.
| Rule | Subject | What it says |
|---|---|---|
| Rule 901(a) | Authentication | There must be evidence sufficient to support a finding that the item is what its proponent claims. |
| Rule 106 | Completeness | When part of a conversation or writing is introduced, the other side may require or introduce the rest. |
| Rule 801 | Hearsay | A party's own statement offered against that party is not hearsay. Other out-of-court statements offered for their truth are. |
| Rules 1002 to 1004 | Originals and copies | The original is required to prove content, but a duplicate is generally admissible unless authenticity is genuinely questioned. |
Authentication Under Rule 901
Rule 901(a) states the test: authentication "is satisfied by evidence sufficient to support a finding that the matter in question is what its proponent claims." The rule then gives examples, by way of illustration only. Those most relevant to messages and photos are:
- Testimony of a witness with knowledge that the item is what it is claimed to be (Rule 901(b)(1)). A person who sent or received a message, or who took a photo, can usually provide this.
- Distinctive characteristics: appearance, contents, substance, internal patterns, taken with the circumstances (Rule 901(b)(4)). A message that refers to things only one person would know is an example.
- A process or system: evidence describing a process used to produce a result and showing it produces an accurate result (Rule 901(b)(9)). This is how forensic extractions and business records of a provider are often supported.
Authentication is a threshold. Once it is met, the judge or jury still decides how much weight the item deserves. A dispute about who was actually holding the phone, or whether an account was shared, can be argued at both stages.
Screenshots Versus Full Records
A screenshot shows what was on a screen at one moment. It may leave out earlier and later messages, it may not show the date or the full phone number, and it can be cropped. That does not make screenshots inadmissible, but it gives the other side something to question.
Two rules address this directly:
- Rule 106. When part of a conversation, writing, or recorded statement is introduced, an adverse party may require the introduction at that time of any other part that ought in fairness to be considered, or may introduce it. A one-sided excerpt invites the rest.
- Rules 1002 and 1003. The original is required to prove the content of a writing, recording, or photograph, but a duplicate is admissible to the same extent unless a genuine question is raised about the authenticity of the original or it would be unfair to admit the duplicate.
For that reason, keep the phone and the complete threads. Give your lawyer the device or a full export, and do not select the messages you think help. Context that seems unhelpful to you may be what makes the rest credible.
Your Messages and the Other Person's
Hearsay is an out-of-court statement offered to prove the truth of what it asserts (Rule 801(c)). Your own statements, offered against you by the State, are not hearsay (Rule 801(d)(2)). The other person's messages, if offered to prove that what they say is true, can draw a hearsay objection, and whether an exception or another purpose applies is decided item by item.
Prior statements can also be used to question a witness whose testimony differs from what he or she wrote earlier (Rule 613). That is one of the main ways the defense uses message history.
Deleted Messages and Missing Data
Do not delete, edit, or "clean up" anything on your phone, your accounts, or your cloud storage once you know there is or may be an investigation. MCA § 45-7-207 makes it a felony, punishable by up to 10 years in prison or a fine of up to $50,000 or both, to alter, destroy, conceal, or remove a record with purpose to impair its verity or availability, or to present a record knowing it to be false. Beyond the criminal exposure, a gap in a thread is easy to see when the other person's phone still has the whole conversation.
If you believe messages on the other side were deleted, tell your lawyer. Do not ask the other person about it, and do not try to get into that person's phone or accounts. Purposely intercepting an electronic communication is itself an offense (MCA § 45-8-213(3)). When originals have been lost or destroyed, Rule 1004 allows other evidence of their contents, unless the party offering it lost or destroyed them in bad faith.
Our page on preserving evidence for your defense lists what to save and how.
Phone Searches and Extractions
Police sometimes seize a phone at arrest, or ask the other person for theirs. In Riley v. California, No. 13-132 (decided in 2014), the U.S. Supreme Court held that a warrant is generally required before searching the data on a cell phone, even one seized incident to arrest. Article II, section 11 of the Montana Constitution names "electronic data and communications" among the things protected from unreasonable searches and requires a warrant to access them to be supported by probable cause.
When a forensic extraction is done, the defense can ask what tool was used, what was collected, and what was left out. Evidence from an unlawful search can be challenged by a motion to suppress.
Exchange of Evidence Before Trial
On request, the prosecutor must make available all papers, documents, photographs, or tangible objects the State may use at trial (MCA § 46-15-322(1)(d)). The duty runs the other way too. Within 30 days after arraignment, or later if the court permits for good cause, the defendant must make available all papers, documents, photographs, and other tangible objects the defendant may use at trial (MCA § 46-15-323(6)(c)). See discovery in a PFMA case.
Other recordings follow the same rules: see the 911 call as evidence and body cameras, photos, and medical records. Messages themselves can also lead to separate charges, covered in privacy in communications charges. For how evidence fits into a defense, see PFMA defenses.
This page explains Montana and federal law in general as of the 2025 Montana Code Annotated. It is not legal advice about your specific case.