Heck v. State: Probable Cause for CSLI Warrants Requires a Case-Specific “Logical Nexus,” and D.R.E. 702 Demands Reliability—Not Infallibility—for Presumptive Blood Tests

Introduction

In Heck v. State (Del. Apr. 17, 2026), the Delaware Supreme Court affirmed Stephen Heck’s conviction for the first-degree murder of his girlfriend, Cynthia Amalfitano. The appeal centered on three issues: (1) whether a warrant for Heck’s cell-site location information (“CSLI”) was supported by probable cause; (2) whether presumptive blood-test evidence (Bluestar and reduced phenolphthalein, “PPB”) and related expert testimony were admissible under Delaware Rule of Evidence 702 (“D.R.E. 702”); and (3) whether a prosecutor’s closing-argument statement about time-of-death amounted to prosecutorial misconduct under plain-error review.

The Court’s opinion is significant for its practical articulation of how the “logical nexus” requirement applies to CSLI warrants after Carpenter, and for its reaffirmation that D.R.E. 702 is a reliability screen—not a demand for scientific certainty—especially where the jury is clearly informed that a method is presumptive rather than confirmatory.

Summary of the Opinion

  • CSLI suppression denied: The CSLI warrant affidavit established probable cause under a totality-of-the-circumstances analysis, creating a “logical nexus” between Heck’s CSLI and evidence of the murder; the affidavit did not rise or fall on a generalized statement that people often carry phones.
  • Serology evidence admitted: Admission of Bluestar and PPB presumptive blood testing satisfied D.R.E. 702 because the methods were sufficiently reliable; D.R.E. 702 requires reliability, not “infallibility,” and testimony that the tests were non-conclusive mitigated the alleged error.
  • No prosecutorial misconduct (plain error): The prosecutor’s closing statement about time-of-death was likely a mid-sentence mistake rather than an intentional misstatement; in any event, it did not prejudice Heck or undermine trial integrity under the fourth step of the Suber framework.

Analysis

1. Precedents Cited

Search Warrants, Probable Cause, and CSLI

  • Carpenter: The Court treated Carpenter as the constitutional baseline—CSLI generally requires a warrant supported by probable cause. This frames CSLI acquisition as a search requiring traditional warrant rigor.
  • Dorsey v. State: Heck relied heavily on Dorsey v. State to argue that the affidavit failed to connect the “place to be searched” (here, CSLI records) to the crime. The Court distinguished Dorsey because in that case the affidavit did not connect the shooting to the defendant’s vehicles. In contrast, the affidavit here included case-specific facts tying Heck, his phone, and the timeline to the crime.
  • State v. Holden: The Court used State v. Holden for two key principles: (1) probable cause must show a “logical nexus” between the items sought and the place to be searched; and (2) review is confined to the “four corners” of the affidavit.
  • Illinois v. Gates (via United States v. Lauria): The Court reiterated the “fair probability” standard under the totality of circumstances—probable cause is a practical, common-sense judgment.
  • Gardner v. State (quoted within Dorsey v. State): The Court reaffirmed Delaware’s preference for a common-sense reading of affidavits rather than a hypertechnical approach.
  • Franks v. State: Cited to support the idea that even if a challenged portion of an affidavit were excised, probable cause can still stand if the remaining, uncontested allegations suffice—reinforcing the Court’s point that the generalized “people carry phones” averment was not outcome-determinative.

Expert Evidence and D.R.E. 702 Reliability

  • Rodriguez v. State: The Court invoked Rodriguez v. State for the principle that D.R.E. 702’s core function is to ensure scientific evidence is relevant and reliable.
  • Ayala v. State: Central to the Court’s framing. Ayala v. State was used to emphasize: (1) the gatekeeping inquiry is whether testimony is the product of reliable principles and methods; and (2) “reliability” does not mean “infallibility.”
  • In re Paoli R.R. Yard PCB Litigation: The Court relied on this formulation—“grounds...have to be good, not perfect”—to justify admitting presumptive tests that are known to have limitations but are still scientifically useful.

Plain Error and Prosecutorial Misconduct

  • Suber v. State: Served as the Court’s template for plain-error review, including the requirement that the error must jeopardize the fairness and integrity of the trial process (the decisive point in Heck’s misconduct claim).
  • Morales-Garcia v. State: Cited as an example of conducting plain-error review of prosecutorial misconduct claims first raised on appeal.
  • Watson v. State: Used for the sequencing of review—first determine de novo whether misconduct occurred; only then consider plain error.
  • Flonnory v. State: Recognized that prosecutorial misconduct may lie where a prosecutor intentionally misstates evidence to the jury.
  • Wainwright v. State (quoted in Suber v. State): Provided the Delaware definition of “plain error” as a basic, serious, fundamental defect causing manifest injustice or deprivation of a substantial right.
  • Rybicki v. State: Supplied the abuse-of-discretion standard for reviewing denial of suppression after an evidentiary hearing.

2. Legal Reasoning

A. CSLI: Probable Cause and the “Logical Nexus” Must Be Grounded in Case-Specific Facts

The Court’s CSLI analysis proceeds from three controlling propositions: CSLI generally requires a warrant (Carpenter), probable cause is evaluated under a totality-of-the-circumstances “fair probability” test (Illinois v. Gates), and the affidavit must establish a “logical nexus” between evidence sought and the place/records to be searched (State v. Holden).

Heck’s argument targeted a single affidavit averment—“persons who own and/or possess cellular phones often times have the phones on and/or near their person….” He claimed this generalized proposition, plus the fact that he was a suspect, could not supply probable cause absent proof (like surveillance) that he physically had his phone at the critical time.

The Court rejected this “single-averment” framing and emphasized the affidavit’s broader set of facts that tied Heck’s phone to relevant time periods: it asserted Heck possessed his phone before the beach trip; he used it to return a call the day after the murder; and police found it on him. Coupled with video/toll evidence placing him with the victim on the drive back and showing him arriving alone at her residence, the affidavit created a reasonable basis to believe Heck’s CSLI would contain evidence about the route, timing, and locations relevant to the homicide.

The key doctrinal point is the Court’s insistence that the “logical nexus” for CSLI warrants is satisfied by a circumstantial, common-sense linkage between (i) the suspect, (ii) the suspect’s phone, and (iii) the crime’s timeline and movements—without requiring direct visual proof of phone possession at the moment of the crime. The Court also made clear that even removing the “people carry phones” generality, probable cause remained within the affidavit’s four corners (citing Franks v. State by analogy to the excision concept).

B. D.R.E. 702: Presumptive Blood Tests Are Admissible When Methods Are Reliable and Limitations Are Disclosed

Heck sought exclusion of PPB (and, on appeal, also challenged Bluestar) as “unreliable” because both are presumptive tests that indicate possible blood presence, not confirmation. The Court framed the D.R.E. 702 gatekeeping task as a threshold reliability inquiry—not a requirement that the evidence be conclusive. Leaning on Rodriguez v. State and especially Ayala v. State, the Court rejected the notion that D.R.E. 702 demands “infallibility.”

The Court also treated the trial testimony as crucial: the experts described how the tests were performed and acknowledged the tests’ limitations (i.e., presumptive nature). That disclosure functionally shifts the decisive assessment to the jury—limitations become weight, not admissibility—so long as the underlying methods are sufficiently reliable.

Procedurally, the Court narrowed the PPB challenge because Heck had conceded below that PPB was tested, peer-reviewed, and generally accepted—leaving only an error-rate argument. For Bluestar, the Court applied plain-error review because Heck had not properly preserved a D.R.E. 702 reliability challenge at trial. On both, the Court concluded admission was within discretion (or at least not plain error).

C. Closing Argument: Mistake vs. Misconduct and the Centrality of Prejudice Under Plain Error

Heck argued for the first time on appeal that the prosecutor intentionally misrepresented the medical examiner’s time-of-death estimate. Under Watson v. State, the Court first asked de novo whether misconduct occurred. It concluded it did not: the prosecutor’s “24 to 30 to 12 hours” phrasing was “incomprehensible as a concrete timeframe” and was most plausibly a self-corrected misstatement mid-sentence—an inference reinforced by the absence of a contemporaneous objection.

Even assuming arguendo an intentional misstatement, the Court held Heck could not satisfy the prejudice requirement in the Suber v. State plain-error framework. Notably, the purported misstatement (suggesting as much as “30 hours”) would have conflicted with the State’s theory anchored in CSLI and the Sunday-night timeline. Combined with Dr. Collins’s warning that time-of-death was only an estimate, the statement did not jeopardize the fairness or integrity of the proceeding.

3. Impact

  • CSLI warrants in Delaware: The decision reinforces that CSLI probable cause is established through a practical “logical nexus” grounded in the affidavit’s full narrative, not a single generalized proposition about phone-carrying habits. Investigators can support CSLI warrants with circumstantial facts showing the suspect’s routine possession and the phone’s relevance to a movement-based timeline; defendants will face difficulty demanding direct proof (e.g., video of phone possession) as a prerequisite.
  • Affidavit drafting discipline: By distinguishing Dorsey v. State, the Court implicitly instructs that affidavits must articulate a specific connection between the sought records and the crime. For CSLI, that connection can be established by integrating known movements, last-seen evidence, and facts tying the suspect to the phone near the relevant period.
  • D.R.E. 702 and forensic “presumptive” evidence: The opinion strengthens the admissibility pathway for preliminary forensic tests when presented honestly (as presumptive), supported by recognized methodology, and accompanied by explanatory expert testimony. Litigants should expect Delaware courts to treat “non-conclusive” as a weight issue unless the methodology itself is shown to be unreliable.
  • Plain-error prosecutorial-misconduct claims: The Court’s emphasis on prejudice—especially where an alleged misstatement is ambiguous, arguably self-corrected, or inconsistent with the proponent’s theory—signals that unpreserved closing-argument challenges will rarely succeed without a clear showing of trial-integrity harm under Suber v. State.

Complex Concepts Simplified

CSLI (Cell-Site Location Information)
Records held by a phone carrier showing which cell towers a phone connected to at certain times. CSLI can place a phone within a general geographic area, sometimes with varying precision depending on tower density and other factors.
Probable cause
A common-sense, practical standard requiring a “fair probability” that evidence of a crime will be found in the place (or records) to be searched. It does not require certainty.
“Logical nexus”
The required connection between what police seek (evidence/records) and where they seek it (a location, device, or dataset like CSLI). The affidavit must explain why the search target likely contains evidence.
“Four corners” review
The judge assesses probable cause based only on what is written in the affidavit—not later explanations or outside facts.
Presumptive blood tests (Bluestar/PPB)
Screening tests that indicate the possible presence of blood (via reactions to hemoglobin/heme), but do not conclusively prove a stain is human blood. Their value is often in guiding further collection and testing (including DNA analysis).
D.R.E. 702 reliability vs. infallibility
D.R.E. 702 asks whether the expert’s methods are reliable enough to help the jury. The method need not be perfect or conclusive; disclosed limitations typically go to weight.
Plain error
A demanding standard for unpreserved issues on appeal. The error must be fundamental and must undermine substantial rights or the fairness and integrity of the trial.
Prosecutorial misconduct
Improper conduct by the prosecutor (e.g., intentionally misstating evidence). Even where misconduct occurs, reversal typically requires a showing of prejudice.

Conclusion

Heck v. State affirms three core principles. First, CSLI warrants satisfy probable cause when the affidavit—read as a whole—creates a case-specific “logical nexus” between the suspect’s CSLI and evidence of the crime; Delaware courts will not require direct proof of phone possession at the critical moment if circumstantial facts reasonably establish the phone’s relevance. Second, D.R.E. 702 admits scientifically useful but non-conclusive forensic methods when they are reliably applied and their limitations are candidly explained—reliability, not infallibility, is the touchstone. Third, unpreserved claims of prosecutorial misstatement in closing argument will fail absent clear misconduct and a concrete showing that the error undermined the trial’s fairness and integrity under Suber v. State.