By Daniel Kugler*

Do allegations of terrorist conduct along with the accused’s unrelated criminal records, establish probable cause under the Fourth Amendment? In this Contribution, Daniel Kugler (’19) discusses how circuits have approached this and similar questions using the Supreme Court’s totality of the circumstances framework. This Contribution argues that an ex-spouse’s allegations of terrorism—such as stockpiling weapons and posting terrorist propaganda on social media—are insufficient to establish probable cause to search for contraband when accompanied only by the accused’s unrelated criminal records.

The Fourth Amendment provides that warrants must be supported by probable cause and “particularly [describe] the place to be searched, and the persons or things to be seized.”2 Determining whether probable cause exists is both a nebulous fact-intensive inquiry under the “totality of the circumstances” analysis and a crucial safeguard against unconstitutional searches.3 Courts consistently confront and must apply this analysis to new and unsettled factual circumstances. It remains undecided whether probable cause to issue a search warrant for evidence of terrorism exists where the magistrate is only presented with a tipster who alleges their ex-spouse is a terrorist and the accused’s unrelated criminal records. Although fact-specific, as probable cause analyses must be, the issues addressed in this Contribution have significant ramifications given the gravity of alleging terrorism and the mass number of Americans with criminal records.

This Contribution will argue that a warrant based on a citizen’s unrelated criminal records and their former spouse’s generalized allegations of terrorism lacks probable cause.

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A magistrate determines probable cause by weighing the “totality of the circumstances,” which include the “veracity,” “basis of knowledge,” and other “indicia of reliability” of persons supplying information for the search warrant affidavit.4 Although each of these factors need not be present and strength in one factor may compensate for weakness in another, the absence of either veracity or basis of knowledge weighs against finding probable cause.5 This framework, established by the Supreme Court in Illinois v. Gates, replaced the prior two-prong test with a “practical, common-sense approach” involving these “intertwined” elements.6 Courts’ analysis of these elements—veracity, basis of knowledge, and alternative indicia of reliability—provides guidance for assessing tips of terrorism and the relevance of the accused’s criminal past.

Veracity is strongest when the tip includes police corroboration and predictive information susceptible to corroboration—e.g. the accused will commit X crime on Y street at Z future time.7verification of those alleged posts is an efficient and effective method for strengthening the veracity of the tip. Law enforcement can typically access social media accounts, including Twitter, because they are visible to the “public by default”8 and even where social media accounts are set to “private” and only visible to “friends” or “followers,” law enforcement can view and verify alleged posts with the assistance of the tipster or use of a confidential informant.9

A basis of knowledge is established by detailed information based on an informant’s personal and recent observations. Even an informant’s former marital relationship to the accused, however, is insufficient alone to establish a sufficient basis of knowledge.10 In United States v. Flynn, the Fifth Circuit explained that informants with an intimate connection to the accused “may have personal reasons for giving shaded or otherwise inaccurate information to law enforcement officials,” and therefore it is inappropriate to presume a basis of knowledge based on that relationship.11

Where there is neither strong veracity in the allegations made nor a strong showing of basis of knowledge, no probable cause exists under the totality of the circumstances absent other indicia of reliability capable of overcoming these deficiencies.12 Law enforcement may contend that both an accused’s prior criminal record and the nature of terrorism allegations should constitute such alternative indicia of reliability.

Although an issue of first impression, existing Fourth Amendment jurisprudence suggests that an accused’s criminal record—including prior convictions and outstanding arrest warrants—unrelated to the offense named in the warrant application does not establish a strong indicium of reliability or probable cause. In Brinegar v. United States, the Supreme Court held that an officer’s knowledge that he had arrested the same defendant months earlier for the same crime suspected, and that the defendant had been indicted for it, properly contributed to finding probable cause to search the defendant for contraband of that crime.13 The Ninth Circuit interpreted this to mean that a defendant’s criminal history may be relevant to the probable cause calculus, but it cautioned, consistent with other circuits, that criminal history “cannot alone establish reasonable suspicion or probable cause.”14

The extent to which the grave nature of terrorism allegations constitutes a strong indicium of reliability also remains unsettled. In Florida v. J.L., the Supreme Court suggested that an anonymous tip may allege danger so great—such as an imminent bomb—as to justify a Terry frisk with a diminished showing of reliability.15 The Court further noted in City of Indianapolis v. Edmond that, although vehicle checkpoints for narcotic searches are unconstitutional, checkpoints may be permissible in the context of thwarting an imminent terrorist attack or specific dangerous suspect.16 The Court cautioned, however, that “[t]he gravity of the threat alone cannot be dispositive of questions concerning what means law enforcement officers may employ to pursue a given purpose.”17 These cases suggest the nature of terrorism allegations may be relevant to, but not independently establish, probable cause.

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Generalized allegations of terrorism—such as stockpiling weapons in connection with terrorist propaganda—made by an accused’s former spouse and only corroborated by a records check of the accused should fail to support a finding of probable cause.

First, uncorroborated and generalized allegations of terrorism lodged by the accused’s former spouse support at most a minimal showing of veracity. This is especially true where the allegations refer to propaganda posted on social media and law enforcement fails to substantiate the existence of those posts. Law enforcement routinely accesses social media posts directly or through the assistance of informants, and the failure of law enforcement to attempt these investigative measures or obtain corroborating evidence through social media searches should be considered as part of the “totality of the circumstances.”18

Second, a strong basis of knowledge cannot be inferred from even a tipster’s former marital relationship to the accused.19 Indeed, this type of relationship exposes a risk that the allegations are “shaded or inaccurate” and provoked by personal reasons.20 This risk is particularly strong where the informant and accused may have children together or share financial obligations.21 As the Seventh Circuit has found, an informant’s personal or “financial motive” in the case may weigh heavily in determining even a known informant’s reliability.22

Third, the Supreme Court has stated that a deficiency in veracity or basis of knowledge can only be overcome by a “strong showing as to another” indicia of reliability.23 A record check of the accused, however, should be found insufficient to establish such strong alternative indicia of reliability or to independently establish probable cause. Unrelated prior convictions or outstanding warrants have never before been found sufficient to establish probable cause to search; to do so would eviscerate Fourth Amendment protections by making millions of Americans’ homes subject to intrusive searches. As Justices Sotomayor and Ginsburg have recognized, the states and federal government have expansive and outdated records of outstanding warrants that, if used to support future arrests and convictions, could be called upon selectively and pose the risk of wrongful deprivation of individuals’ liberties.24 At most, the existence or absence of an accused’s criminal records should be considered one factor among many in determining probable cause.25

Fourth, the nature of terrorism allegations should not be dispositive to the probable cause calculus. To hold otherwise would encourage harassment by false reports of terrorism—that would require less corroboration or knowledge of the informant—without enhancing the reliability of information in the warrant application. While acknowledging the possibility of an exigency exception to Terry based on terrorism, the Court in J.L. ultimately reasoned that requiring a lower standard of reliability for allegations of more dangerous crimes would invite harassment through false reporting of those offenses to law enforcement.26 Justice Ginsburg, in an unanimous opinion for the Court, explained that it “would enable any person seeking to harass another to set in motion an intrusive, embarrassing police search of the targeted person . . . simply by placing an anonymous call . . . ” In reasoning equally applicable to special needs searches and probable cause warrants, the Edmond Court further cautioned that “the gravity of the threat alone cannot be dispositive.”27 Ultimately, warrants “should not be authorized unless there is some assurance that the information on which they are based has been obtained in a reliable way by an honest or credible person.”28

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The Supreme Court in Gates moved away from a rigid formula of probable cause and toward a fact-intensive inquiry under “the totality of the circumstances.” Although no longer required in every case, strong veracity and basis of knowledge remain important factors in a probable cause analysis that can only be displaced by equally strong alternative indicia of reliability. Where there is an allegation of terrorism with weak veracity and the basis of knowledge must be inferred from the informant’s prior marriage to the accused, the accused’s criminal record and the nature of the threat alleged should not constitute strong indicia of reliability sufficient to establish probable cause.

* Daniel Kugler is a 3L at New York University School of Law. This piece is a commentary on a problem written for the 2018 Herbert Wechsler National Criminal Moot Court Competition at the University of Buffalo School of Law. The issue presented in the problem focused on whether a search warrant—consisting of terrorism allegations made by the defendant’s former wife and the defendant’s criminal records—contained probable cause under Illinois v. Gates, 462 U.S. 213 (1983) and sufficient veracity under Franks v. Delaware, 438 U.S. 154 (1978), despite the affiant’s inclusion of false information and omission of material facts.

2. U.S. Const. amend. IV.

3. Illinois v. Gates, 462 U.S. 213, 238 (1983).

4. Gates, 462 U.S. at 230.

5. Id.

6. Id. at 216, 230, 238; see generally Aguilar v. Texas, 378 U.S. 108 (1964); Spinelli v. United States, 393 U.S. 410 (1969).

7. Gates, 462 U.S. at 244-45 (“corroboration through other sources of information [can] reduce[] the  chances of a reckless or prevaricating tale” (quoting Jones v. United States, 362 U.S. 257, 271 (1960))).

8. See About Public and Protected Tweets, Twitter, (last visited February 18, 2018).

9. See, e.g., United States v. Meregildo, 883 F. Supp. 2d 523, 526 (S.D.N.Y. 2012) (upholding probable cause of search warrant based on government access to defendant’s Facebook profile); Perry v. Montgomery, No. CV-16-03730-FMO (KES), 2017 U.S. Dist. LEXIS 95077, at *35 (C.D. Cal. June 5, 2017) (finding no Fourth Amendment violation by confidential informant’s warrantless seizure of suspect’s Instagram photo).

10. See United States v. Flynn, 664 F.2d 1296, 1302-03 (5th Cir.), cert. denied, 456 U.S. 930 (1982).

11. Id.

12. United States v. Hicks, No. 5:12-CR-00006-TBR, 2012 U.S. Dist. LEXIS 137189, at *12 (W.D. Ky. Sep. 24, 2012) (reversing probable cause finding and giving no weight to uncorroborated tip by defendant’s ex-wife that made general allegations that defendant’s computer had viewed child pornography); see, e.g., United States v. Peck, 317 F.3d 754, 757 (7th Cir. 2003) (finding no probable cause where defendant’s girlfriend’s tip lacked “specific detail” about the drugs he possessed, the location of drugs within his house, or his frequency of drug deals, and police only corroborated defendant’s criminal record).

13. Brinegar v. United States, 338 U.S. 160, 175-76 (1949).

14. Burrell v. McIlroy, 464 F.3d 853, 858 n.3 (9th Cir. 2006) (finding that criminal history “cannot alone establish reasonable suspicion or probable cause”) (citing Brinegar, 338 U.S. at 177 (1949)); see Peck, 317 F.3d at 757 (“[P]olice must do more than simply run a record check of the accused, because this alone does not corroborate a CI’s statements alleging that a search will uncover evidence of a crime.”).

15. Florida v. J.L., 529 U.S. 266, 273-74 (2000).

16. City of Indianapolis v. Edmond, 531 U.S. 32, 44 (2000).

17. Id. at 42.

18. See Meregildo, 883 F. Supp. 2d at 526; Perry, No. CV-16-03730-FMO (KES), at *35.

19. See Flynn, 664 F.2d at 1302-03.

20. See id.

21. See also United States v. Grover, 755 F.3d 811, 817 (7th Cir. 2014) (finding informant’s “financial motive” relevant to determining probable cause).

22. Id.

23. Gates, 462 U.S. at 230.

24. See Utah v. Strieff, 136 S. Ct. 2056, 2068 (2016) (Sotomayor, J., dissenting) (“The States and Federal Government maintain databases with over 7.8 million outstanding warrants, the vast majority of which appear to be for minor offenses.”); Herring v. United States, 555 U.S. 135, 155 (2009) (Ginsburg, J., dissenting) (asserting that “[i]naccuracies in expansive, interconnected collections of electronic information,” including outstanding warrants, “raise grave concerns for individual liberty”).

25. See Brinegar, 338 U.S. at 175-76 (finding the arresting officer’s arrest of the defendant for the same crime months earlier relevant to determining probable cause); Burrell, 464 F.3d at 858 n. 3 (finding criminal records alone insufficient for probable cause); Peck, 317 F.3d at 757 (finding a check of the accused’s criminal record insufficient corroboration to establish probable cause).

26. J.L., 529 U.S. at 272-73 (“Such an [automatic firearm] exception [to Terry reliability analysis] would enable any person seeking to harass another to set in motion an intrusive, embarrassing police search of the targeted person simply by placing an anonymous call falsely reporting the target’s unlawful carriage of a gun.”).

27. Edmond, 531 U.S. at 42.

28. Gates, 462 U.S. at 283.