A landlord posts on Facebook: “changed the locks on 4B—pay up or get out.” A few hours later, he deletes it. His tenant, locked out of her apartment, takes a screenshot before it disappears. Months later, that screenshot becomes the key evidence in her wrongful eviction lawsuit against him.

Her case isn't unique. Between someone hitting “post” and that screenshot getting anywhere near a jury, a lawyer has to do a lot of work to make sure it holds up. That work usually happens months earlier, in a deposition.

The Authentication Problem

Take the example above. There’s nothing stopping the landlord from claiming he never wrote that post at all. Before a screenshot can do any work in court, someone has to prove he’s the one who wrote it. That’s called authentication.

In litigation, authentication means proving a piece of evidence is what it claims to be. For a social media post, the question is: did the person whose name is on the account actually write it?

A name and profile photo alone aren’t enough. An account can be created under someone else’s name, shared across multiple people with the same login, or compromised by a hacker. Then there’s catfishing, which involves creating a fake identity from scratch, complete with a stolen photo, to pose as someone else entirely.

For example, imagine a custody dispute where the father claims the mother is an unfit caregiver. A post appears on the mother’s account: “kids are with their dad this week, time to party!! 🍾🎉”

It looks damning—until you consider who else could have posted it. The name and photo on the account can’t answer that question.

Proving who posted what requires more. An attorney can examine the device used to create the post, have the social media platform confirm the account holder’s identity, or they can ask the person directly if they wrote it. Asking directly is the simplest and most common way to authenticate posts—and it happens at the deposition. Getting someone to admit, under oath, that they wrote a post locks down authenticity before trial.

The Lock-In Technique

Before the deposition starts, the attorney has the screenshot ready to go, prepped as an exhibit ahead of time. Platforms like Steno Connect enable attorneys to pre-upload exhibits, so when it’s time to present, there’s zero scrambling or delay.

Once the deposition begins, the attorney doesn’t show the witness the screenshot right away. Instead, they start with a few seemingly harmless questions. Is this your account? Are you the only one with access to it? Does anyone else ever post from it? Does anyone else know the password?

These questions are a trap, designed to get the witness to make simple, comfortable admissions before they know why they’re being asked.

Only after those admissions does the attorney introduce the screenshot and ask the witness if they wrote the post. By then, backing out isn’t really an option. Denying authorship means at least one of those previous answers wasn’t true, which would make the witness look dishonest to everyone in the room and, eventually, to the jury.

Either they admit to writing the post, and it’s authenticated for use at trial, or they backtrack and lose credibility at trial.

Covering All Your Bases

Before the deposition wraps, a thorough lawyer will ask two more questions. First, they’ll ask whether the witness has deleted or deactivated any social media accounts, or deleted or edited any posts since they were on notice of litigation. This is known as a spoliation question.

Spoliation is the legal term for destroying evidence. Once someone knows they’re likely to be involved in a lawsuit, they have an obligation to preserve anything relevant to the subject of that lawsuit, including social media posts. If it later comes out that a witness deleted something they shouldn’t have, they become vulnerable to a spoliation claim.

Finally, the attorney will ask what other social media accounts the witness might have. This is an impeachment question. Impeachment means using a witness’s prior statements to undercut their believability before a jury. If a subpoena or a discovery request later turns up an account the witness never mentioned, especially one with something damaging on it, the witness now looks like they were hiding that account.

Asking both questions during the deposition cements the witness’s answers by getting them on the record. If either one turns out to be false, the deposition transcript is what catches the lie.

From Post to Proof

Months after that Facebook post disappeared, the landlord sits for his deposition. The tenant’s attorney starts easy, asking, “Is this your account? Does anyone else have access to it?” Then, only after he’s answered, she pulls up the screenshot. He can deny writing it, but that means contradicting what he just said under oath.

He admits it. The screenshot is authenticated, and “pay up or get out” is now evidence in his own words. It’s a small, deliberate sequence of questions, and it’s exactly how a deleted post can end up deciding a case.