Who sent it? Authenticating text messages
Social media is becoming more prevalent in trials. From emails to texts to Facebook posts, social media can be critical evidence that a party must get in. So how is it done? Well as with any piece of evidence, there will likely be multiple rules of evidence in play. This will range from authentication to hearsay to best evidence. So start in order.

Authentication
The first step is to prove that the item is what it claims to be. Social media exhibits are usually printed out versions of the message. Whether that be a Facebook post, a Tweet, or a string of text messages, the exhibit will usually be a handful of paper. That means that the proponent first needs to prove that the handful of paper is what they are claiming it to be. Look to Rule 901 and treat the exhibit just like authenticating any other exhibit:
Rule 901, SCRE, does not care what form the writing takes, be it a letter, a telegram, a postcard, a fax, an email, a text, graffiti, a billboard, or a Facebook message. All that matters is whether it can be authenticated, for the rule was put in place to deter fraud.
Text messages can present a common problem of "who sent it?" The question of who sent it is important for several reasons. First, who sent the message will make it relevant. For example, if the State is entering the defendant's text messages to show knowledge, then if he didn't send them, then the messages are likely not relevant. Second, who sent the messages will affect other rules, particularly hearsay. So how do you prove who sent the text message? Well it looks like this could go one of two ways. The trial judge might need to make a ruling under Rule 104(b) to determine who sent the messages in order to determine if they are relevant. Click here for a post on that. Or it could be completely determined by authentication.
In a Texas case, Butler v. State, 459 S.W.3d 595, 602 (Tex. Crim. App. 2015), the court explained the issues behind text messages and possible methods for authenticating the sender:

Text messages can be compared to return labels:


If the text messages are properly authenticated, then the next issue to address would be hearsay. But we will save that for another blog post.