A reader pointed to a recent article about a child pornography prosecution. The defendant, it turns out, had posted to Facebook “actively discussing child pornography and methods for downloading pornography from the Internet,” and the FBI apparently used the defendant’s statement (coupled with other statements that showed interest in child pornography) as probable cause to get a search warrant of defendant’s home computer — which turned out to indeed contain child pornography. I responded that I didn’t see anything necessarily wrong with this.
The reader then replied:
[Y]ou said … that it is perfectly acceptable for law enforcement to use a person’s statements on Facebook as probable cause to obtain a warrant to search their computer for child pornography. Would it also be OK to so use a person’s Google search? A private conversation? An utterance one makes in one’s sleep? (If your answer to all these questions is “yes”, I suggest you reread George Orwell’s “1984”.)
So here’s the thing: Using a person’s ”private conversation” as probable cause to get a warrant to search for evidence is utterly commonplace, and indeed quite necessary. Say that the police are investigating who killed Violet Victim, and Don Defendant had said to Walter Witness that he had Violet’s body in his freezer. Of course such a statement could be used, and should be used, in determining whether there is probable cause to search Don’s house.
Of course, it might not itself be proof beyond a reasonable doubt that Don killed Violet. Maybe Don was joking, or was lying to Walter for some reason, or was deluded. But the point of searches is to uncover evidence that may help decide whether there is proof of guilt beyond a reasonable doubt. This is why the standard required for searches is the far lower “probable cause.” And a person’s own statement about what he supposedly did is pretty powerful evidence for showing such probable cause.
This is so whether Walter voluntarily tells the police about Don’s statement, Don’s statement to Walter is overhead by another citizen who reports it, Don’s statement is recorded on a lawful wiretap (which was itself gotten based on probable cause), or Walter is compelled to testify before a grand jury about his conversation with Don. In all these cases, Don’s statements, as reported by Walter, are precisely the sort of evidence that would be and should be used in determining probable cause, or in helping prove guilt beyond a reasonable doubt at a criminal trial.
Does the admissibility of speech as evidence have a “chilling effect” on speech? Sure. But I can’t see how the alternative — never using a person’s voluntary out-of-court statements as evidence against him (or perhaps even against his friends, if you’re really so concerned about chilling effects), even though they are often the most reliable evidence, especially of matters such as knowledge or intent — could work.
Now of course this rule can easily be misused by totalitarian regimes (even ones that do not use 1984’s model of continuous physical surveillance inside people’s homes). Many such regimes have indeed heavily relied on people reporting, say, political dissent by their acquaintances. But pretty much all crime-fighting techniques can be, and have been, misused by totalitarian regimes (and, more relevant to our discussion, by non-totalitarian regimes that are nonetheless acting abusively towards some citizens): Consider, for instance, prisons, police departments, and the criminal justice process itself. Yet this risk of misuse is generally a reason to impose some legal and political constraints on such institutions, not to abandon prisons, police departments, and the criminal justice process altogether.
Likewise, I think, with regard to the use of speech as evidence. We avoid oppression not by refusing to use people’s reports of admissions of guilt by their acquaintances, but, for instance, by having First Amendment rules that limit the range of crimes that can be prosecuted. An acquaintance’s statement to the police that I think the Obama Administration has been bad for the country is not going to lead to a conviction for seditious libel or “anti-government propaganda” (to borrow a term from Communist regimes), simply because the government may not declare such behavior to be criminal. Likewise, unlike in the 1984 world, a magistrate must indeed find probable cause for a search, and many statements will not offer such probable cause.
This being so, I think that the use of Facebook statements as evidence is no more troublesome. If someone says something on Facebook that strongly suggests that he killed his wife, or that he robbed someone, or that he has downloaded child pornography, that can rightly be used as evidence supporting probable cause for a search warrant. In some situations, it may be poor evidence, but in many situations it may be strong evidence indeed.
The same case-by-case inquiry into whether the statement provides probable cause should in principle apply to Google searches (e.g., “how to hide my stash of child pornography” or “how to hide a dead body”) and to utterances in one’s sleep. In those cases the result would often be that such statements are not sufficient to show probable cause. Google searches are generally much less specific than Facebook posts, and are less inculpatory than Facebook statements that (without any contextual cues suggesting humor or fiction) say “I did this-and-such.” Statements in one’s sleep might likewise often reflect dreams or fears more than actual experiences, though I don’t know what the empirical research in that area suggests.
Still, the bottom line question remains: Does this statement, viewed in context and together with other evidence the police have, establish probable cause to believe that a search of a particular place will yield evidence of a crime? If the answer is yes, that statement is admissible, fears of 1984 notwithstanding.