Supreme Court, New York County, December 5, 2025

OPINION OF THE COURT

Juan M. Merchan, J. {**89 Misc 3d at 297}

Procedural Background

Defendant is charged with murder in the second degree, in violation of Penal Law § 125.25 (2), manslaughter in the first degree, in violation of Penal Law § 125.20 (4), reckless assault of a child, in violation of Penal Law § 120.02, and endangering the welfare of a child, in violation of Penal Law § 260.10 (1). The People allege that on or about September 21, 2020, the defendant caused the death of three-month-old K.M. who had been left in defendant's care by K.M.'s mother, M.M. Specifically, the People allege that at approximately 8:12 p.m. on September 21, 2020, the defendant called 911 and stated "my stepson was crying . . . my son is not breathing." First responders transported the child to New York Presbyterian Downtown Hospital. K.M. was later pronounced dead on September 23, 2020. Because the final autopsy report was not issued until several months after K.M.'s death, the defendant was initially only charged with assault in the first degree, in violation of Penal Law § 120.10 (3).

Defendant filed the instant motion on July 18, 2025, seeking to preclude the People from presenting expert testimony on Shaken Baby Syndrome/Abusive Head Trauma (hereinafter SBS/AHT). In the alternative, defendant moves for a Frye hearing pursuant to Frye v United States (293 F 1013 [DC Cir 1923]) challenging the reliability of SBS/AHT. Notably, defendant's motion did not address the "science regarding shaking-plus-impact." (Defendant's mem at n 18 [emphasis added].) In conjunction with that motion, defendant also moves this court to hold that the third count in the indictment charging him with reckless assault of a child should be deemed unconstitutionally vague and dismissed.

The People responded on August 15, 2025. At a hearing conducted before this court on August 20, 2025, the People indicated that they intend to call experts to testify to SBS/AHT both with and without impact. (Aug. 20, 2025 hearing tr at 15 ["Certainly shaking plus blunt force trauma could lead to these injuries, but so could a constellation of other actions"].) As such, the People requested that this court rule on defendant's Frye[*2]motion.^FN1 As a result, defendant supplemented his motion on August 22, 2025, and the People responded on August 25, 2025.

{**89 Misc 3d at 298}Defendant argues that there exists serious debate in the medical, academic, and legal communities surrounding SBS/AHT and that there has been a lack of "judicial scrutiny" surrounding such expert testimony in New York. (Defendant's mem at 5.) Defendant's motion lies squarely with the People's intent to have expert testimony on their direct case as to SBS/AHT being the sole cause of death of the child, and not the introduction of "SBS/AHT plus" testimony.

The People assert that acceptance of expert testimony on this subject is well-settled in New York courts and that the legislative intent behind the promulgation of Penal Law § 120.02 demonstrates that there is no serious debate regarding this topic in the New York legal community. Finally, the People urge this court to reject defendant's argument with respect to the reckless assault of a child count since the statute is clear as to the conduct it prohibits.

Controlling Law

In evaluating the admissibility of expert testimony grounded in scientific principles, New York courts apply the standard articulated in Frye v United States (293 F 1013 [DC Cir 1923]). Pursuant to Frye, such testimony may be received only where the underlying scientific method or principle has achieved "general acceptance" within the relevant scientific community. (Id. at 1014.) Under the Frye standard, a court determines the "relevant scientific community" by focusing on the specific principle or procedure an expert's testimony is based upon. As the Court of Appeals has emphasized, "[t]he long-recognized rule of Frye . . . is that expert testimony based on scientific principles or procedures is admissible but only after a principle or procedure has 'gained general acceptance' in its specified field." (People v Wesley, 83 NY2d 417, 422 [1994], quoting Frye, 293 F at 1014.) The Frye inquiry is not concerned with the specific conclusions drawn by the expert, but rather with the reliability of the methodology itself. The test is whether "the accepted techniques, when properly performed, generate results accepted as reliable within the scientific community generally." (Parker v Mobil Oil Corp., 7 NY3d 434, 446 [2006]; Wesley, 83 NY2d at 422.) Absolute unanimity is not required. However, there must be a demonstrable consensus that the methodology is scientifically sound. (People v Middleton, 54 NY2d 42, 49 [1981]; Sean R. v BMW of N. Am., LLC, 26 NY3d 801, 809 [2016].)

{**89 Misc 3d at 299}Once the threshold of general acceptance is met, the court must then consider whether there exists a proper evidentiary foundation to support the introduction of the expert's opinion at trial. (Wesley, 83 NY2d at 429.) This includes ensuring that the expert is qualified, that the opinion is relevant to the issues in the case, and that the subject matter is beyond the ken of the average juror. (People v LeGrand, 8 NY3d 449, 452 [2007]; Jerome Prince, Richardson on Evidence § 7-301 [Farrell 11th ed 1995].) The burden of establishing general acceptance and a sufficient foundation lies squarely with the proponent of the evidence. (People v Price, 29 NY3d 472, 479 [2017]; Styles v [*3]General Motors Corp., 20 AD3d 338, 341 [1st Dept 2005].) A mere showing that an opinion has "some support" or has been endorsed by individual experts does not suffice. The proponent must demonstrate that the methodology has attained broad acceptance within the relevant scientific field. (Cornell v 360 W. 51st St. Realty, LLC, 22 NY3d 762, 782-783 [2014].)

A hearing may be deemed unnecessary where the methodology has already been deemed admissible by other courts in comparable contexts. (See People v Brooks, 31 NY3d 939, 941 [2018]; Wesley, 83 NY2d at 422.) In such cases, judicial precedent may serve as an adequate basis for determining general acceptance.

Respective Arguments

Frye Arguments:

The defendant's primary argument is that he is entitled to a Frye hearing because "there is significant controversy over whether SBS/AHT can be diagnosed without signs of physical injury by impact." (Defendant's mem at 11.) Defendant provides an overview of the history of SBS/AHT along with various scholarly articles and studies to support his position. (Defendant's mem at 13-14.) Defendant's ultimate contention is that "there has not been a single biomechanical study showing that an adult human can shake an infant with enough force to cause subdural hemorrhages or other brain damage." (Defendant's mem at 15.) Defendant argues that despite the alleged split in the scientific community regarding SBS/AHT, the lack of judicial scrutiny by New York courts over the past several decades warrants a Frye hearing and, ultimately, preclusion of the People's expert witnesses. To support the position that SBS/AHT is "not reliable and generally not [an] accepted theory of causation in the scientific medical community," the defendant {**89 Misc 3d at 300}relies primarily upon State v Nieves (476 NJ Super 609, 302 A3d 595 [App Div 2023]), a New Jersey decision recently affirmed by that state's highest court (262 NJ 161, 345 A3d 1127 [2025]). Lastly, defendant argues that if this court does not grant defendant's request for a Frye hearing, then it is essentially "shifting the burden of proof to the Defendant." (Defendant's mem at 27.)

The People contend that SBS/AHT is well-recognized and generally accepted as an appropriate subject for expert testimony not only in courts across the United States but, more importantly, it is the controlling precedent in New York courts. (People's opp at 4.) They further cite, as People's exhibit 4, a report published by the American Academy of Pediatrics^FN2 and the legislative history to Penal Law § 120.02 which provide that SBS/AHT is "well-recognized and widely accepted in the scientific, medical, and legal community." (Id.) As such, the People submit, there is no need for a Frye hearing, nor does the introduction of such evidence shift the burden of proof to the defendant. (Id. at 5, 10-11; exhibit 4.) The People argue that their "evidence is always necessarily prejudicial to defendant—that doesn't mean the presentation of such evidence is burden shifting." (Id. at 11.)

Reckless Assault of a Child:

Defendant's final argument flows from his first, to wit, because this court should hold that SBS/AHT is not generally accepted within the scientific community it must therefore also [*4]find that the charge of reckless assault of a child is unconstitutionally vague and dismiss that count of the indictment.

The People argue that because SBS/AHT is generally accepted as appropriate evidence in New York State, and since the legislative intent of the charge of reckless assault of a child is clear regarding the conduct it prohibits, there is no reason to find the statute unconstitutionally vague.

Discussion

Defendant's motion to preclude expert testimony regarding SBS/AHT or in the alternative, that this court grant a Frye hearing is denied. Likewise, defendant's motion, that this court find the crime of reckless assault of a child unconstitutionally vague as applied to this matter, is also denied.

{**89 Misc 3d at 301}As aptly acknowledged by Justice Cyrulnik in People v Flores-Estrada, "[b]ased upon the scientific literature and case law, it is undeniable that there exists a faction of the scientific community that challenges SBS/AHT, and that 'a significant and legitimate debate in the medical community [about this issue] has developed in the past ten years.' " (People v Flores-Estrada, 55 Misc 3d 1015, 1018 [Sup Ct, Kings County 2017], citing People v Bailey, 144 AD3d 1562, 1564 [4th Dept 2016].) Just as the defense argued in Flores-Estrada, the defendant here relies on a number of scholarly articles and decisions from jurisdictions outside the State of New York to support his motion. However, in denying Flores-Estrada's motion for a Frye hearing, Justice Cyrulnik recognized that "New York courts have specifically held that SBS/AHT is generally accepted" as reliable. (Flores-Estrada, 55 Misc 3d at 1017, citing People v Yates, 290 AD2d 888 [3d Dept 2002], Matter of Antoine J., 185 AD2d 925 [2d Dept 1992], People v Thomas, 46 Misc 3d 945 [Westchester County Ct 2014], and Matter of Lou R., 131 Misc 2d 138 [Fam Ct, Onondaga County 1986].) This steady stream of rulings by New York courts has been reinforced as recently as October 29, 2024, by Justice Pandit-Durant in People v Callaghan (Sup Ct, Queens County, Oct. 29, 2024, indictment No. 2348/2018). Stated simply, New York courts, have historically and presently, ruled in favor of allowing expert testimony regarding SBS/AHT.

This court acknowledges, as did Justice Pandit-Durant, the well-reasoned decision by New Jersey's intermediate appellate court in State v Nieves (476 NJ Super 609, 302 A3d 609 [App Div 2023]). However, Nieves is not controlling upon this court. Indeed, the well-settled authority in New York, which this court is required to follow, establishes that expert witness testimony regarding SBS/AHT is permitted at trial without the need for a Frye hearing. As held in Callaghan, no Frye hearing is necessary where a court "can rely upon previous rulings in other court proceedings as an aid in determining the admissibility of the proffered testimony." (Callaghan, Sup Ct, Queens County, Oct. 29, 2024, Pandit-Durant, J., indictment No. 2348/2018, citing People v LeGrand, 8 NY3d 449, 457-458 [2007].)

The legislative intent behind Penal Law § 120.02 only serves to reaffirm New York's view that expert testimony regarding SBS/AHT is admissible. The documents contained within the Bill Jacket for Penal Law § 120.02 detail the enactment of "Cynthia's Law" in New York, a bill that was drafted upon the {**89 Misc 3d at 302}death of Cynthia Gibbs, who was eight months old at the time. (People's exhibit 4; Bill Jacket, L 2006, ch 110.) In fact, Penal Law § 120.02 was enacted to address the incidence of SBS/AHT. Indeed, the enactment was accompanied by a public awareness campaign addressing [*5]the tragic effects that SBS/AHT could have on infants and young children. (Id.) Further, as noted by Judge Zambelli, SBS/AHT has been "recognized by such governmental organizations as the Centers for Disease Control and Prevention and the National Institute of Neurological Disorders and Stroke, a component institute of the National Institutes of Health." (People v Thomas, 46 Misc 3d 945, 950 [Westchester County Ct 2014].) It is clear from this court's reading of the various letters and memos within the Jacket, including the memo from the State of New York Department of Health, that the legislative intent is echoed in the numerous cases that have upheld SBS/AHT expert testimony within New York and that the New York State Legislature agrees.

In the context of SBS/AHT, courts have examined the views of both the biomechanical and pediatric medical communities. (Thomas, 46 Misc 3d at 945.) "The scientific procedures in question need not be 'unanimously indorsed' by the scientific community, but must be 'generally acceptable as reliable.' " (People v Debraux, 50 Misc 3d 247 [Sup Ct, NY County 2015], citing People v Middleton, 54 NY2d 42, 49 [1981].) In the context of "relevant scientific community," this court finds highly persuasive the 2025 report from the American Academy of Pediatrics titled "Abusive Head Trauma in Infants and Children: A Technical Report." The report acknowledges that biomechanical studies can be helpful but concludes that they contain inherent limitations that must be carefully considered when interpreting its data. As it stands, New York courts have consistently held that SBS/AHT evidence is generally accepted by the relevant medical and scientific communities. Unless and until it is held otherwise by an appellate court, this court is compelled to follow binding precedent. (People v Van Norstrand, 85 NY2d 131 [1995]; People v Wong, 81 NY2d 600 [1993]; People v Hershey, 85 AD3d 1661 [4th Dept 2011], lv denied 18 NY3d 883 [2012].)

Finally, the defendant's motion to dismiss the third count of the indictment as unconstitutionally vague is denied. Precedent within this state indicates a general acceptance of SBS/AHT and the reckless assault of a child statute provides a person "of ordinary intelligence fair notice that his contemplated {**89 Misc 3d at 303}conduct is forbidden by the statute" and provides officials with "clear standards for enforcement." (People v Stuart, 100 NY2d 412, 420 [2003].) There is no ambiguity as to what conduct this statute prohibits.

Conclusion

This court finds that SBS/AHT has gained general acceptance within the relevant scientific community in New York. This acceptance, coupled with the clear controlling legal precedent in New York and the legislative history behind the enactment of Penal Law § 120.02, reckless assault of a child, requires that defendant's motion to preclude expert witness testimony on SBS/AHT or in the alternative, for a Frye hearing, be denied.

Defendant's motion to dismiss the third count of the indictment, reckless assault of a child in violation of Penal Law § 120.02, as unconstitutionally vague is also denied.