Clarifying Due Diligence Standards for CPL 245 Certificates of Compliance: People v. McMahon

Introduction

In People v. McMahon (2025 NYSlipOp 01951), the Appellate Division, Second Department, addressed for the first time in depth the interplay between New York’s discovery‐certificate regime (CPL 245) and the statutory speedy‐trial clock (CPL 30.30). The defendant, Darren McMahon, Jr., was charged with aggravated cruelty to animals after allegedly killing ducks in his backyard. After multiple rounds of discovery and three Certificates of Compliance (COCs), the Supreme Court, Suffolk County, granted McMahon’s motion to dismiss for violation of his CPL 30.30 speedy‐trial rights on the ground that the People had filed “illusory” COCs under CPL 245. The Appellate Division reversed, reinstating the indictment and remitting for trial.

Key issues:

• What constitutes “due diligence” and “reasonable inquiries” under CPL 245.50(1) when filing a COC?
• When may an automatic discovery certificate excuse exclusion of time under CPL 30.30?
• What remedial standards govern dismissal under CPL 245.80 for late or incomplete discovery?

Parties:

• The People of the State of New York (Appellant)
• Darren McMahon, Jr. (Respondent/Defendant)
• Supreme Court, Suffolk County (Justice Horowitz)
• Appellate Division, Second Department (Justices Iannacci, Ford, Taylor, McCormack)

Summary of the Judgment

The Appellate Division reversed the trial court’s dismissal of the indictment. It held that:

1. The People satisfied their burden under CPL 245.50(1) of exercising “due diligence” and making “reasonable inquiries” before filing the December 15, 2022 COC, despite later‐discovered missing detective notes.
2. Under People v. Bay (41 NY3d 200), due diligence is a flexible, holistic standard that does not demand perfection or impose strict liability on prosecutors acting in good faith.
3. Because the COC was proper, the related readiness statement was not illusory, and fewer than 120 days were chargeable to the People for speedy‐trial purposes. The case remained within the six‐month CPL 30.30 window.

The order of the Supreme Court was reversed, the defendant’s motion to dismiss under CPL 30.30(1)(a) was denied, the indictment reinstated, and the case remitted for further proceedings.

Analysis

1. Precedents Cited

• People v. Bay (41 NY3d 200): Articulated six non-exhaustive factors for evaluating due diligence under CPL 245.50(1), and emphasized that dismissal under CPL 245.80(2) is a remedy of last resort, requiring proportionality analysis.
• People v. Drayton (231 AD3d 1057): Confirmed the burden on the People to show due diligence before filing a discovery certificate.
• People v. Bolden (81 NY2d 146): Established that good faith alone does not satisfy the CPL 245.50(1) due‐diligence requirement.
• People v. Cooperman (225 AD3d 1216) and People v. Lawrence (231 AD3d 1497): Demonstrated the application of a holistic, case-specific analysis weighing factors such as volume of discovery, complexity, obviousness of missing material, and prosecutors’ procedures.
• People v. Deas (226 AD3d 823) and People v. Macaluso (230 AD3d 1158): Reinforced that inadvertent omissions discovered and corrected promptly do not necessarily defeat due diligence.

2. Legal Reasoning

The court’s decision turns on CPL 245.50(1) and 245.60’s disclosure regime and its bearing on speedy‐trial calculations under CPL 30.30. Under CPL 245.50(1), once automatic discovery has been exchanged, the prosecutor must file a COC certifying that, “after exercising due diligence and making reasonable inquiries,” all known discoverable materials have been disclosed. CPL 245.60 imposes a continuing duty, requiring supplemental COCs when additional discovery surfaces.

In 2022 amendments to CPL 245.80(2), the Legislature prescribed that dismissal of charges is appropriate only after all other remedies are exhausted and the sanction is “proportionate” to the prejudice suffered. People v. Bay provided guidance: due diligence is a flexible, holistic standard measured by factors such as:

1. Efforts by the prosecutor’s office and policies in place
2. Volume and complexity of discovery delivered
3. Obviousness of missing materials to a diligent prosecutor
4. Explanation for any lapse (e.g., oversight vs. bad faith)
5. Promptness of corrective disclosure once the lapse is uncovered

Applying these factors, the court found:

• The Suffolk County DA’s office had instituted discovery‐compliance policies (BEAST Unit, 30 discovery expediters).
• Over 400 pages of initial discovery were produced in good faith.
• The missing pages of Detective Tomlin’s notes were not obviously absent, given that entire categories of discovery were otherwise intact.
• The prosecutor reasonably relied on Detective Tomlin’s representation that her digital file was complete.
• The People immediately supplemented discovery upon learning of each omission.

Under this holistic assessment, the People met their due‐diligence burden when filing the December 2022 COC. Therefore, the readiness statement was not illusory, and the statutory speedy‐trial clock remained tolled for only 120 days—well within the six-month CPL 30.30 limit.

3. Impact

People v. McMahon provides concrete guidance on several fronts:

• It cements the Bay framework as the controlling standard for evaluating due diligence under CPL 245 certificates.
• It affirms that good-faith reliance on a law enforcement officer’s representations, coupled with immediate remedial disclosures, can satisfy the due-diligence requirement.
• It underscores that prosecutors do not face “strict liability” for every inadvertent discovery omission, so long as office protocols and prompt cures demonstrate a reasonable effort.
• It clarifies that improper COCs are the only basis for deeming readiness statements “illusory” and triggering speedy-trial dismissal—mere delays in supplemental disclosures without COC deficiencies will not suffice.

Going forward, defense counsel and trial courts will scrutinize discovery‐compliance policies and timelines to determine whether any certificate was truly filed without due diligence, rather than viewing every late supplement as a per se violation.

Complex Concepts Simplified

• CPL 245 (Discovery Certificates): A statutory scheme requiring the People to disclose all known evidence—witness statements, police reports, Giglio material—then file a certificate stating they have made reasonable efforts to locate and disclose anything else. Supplemental certificates are required if new evidence surfaces.
• CPL 30.30 (Speedy Trial): The People have six months from arraignment to be “ready for trial,” as evidenced by a valid certificate of compliance and readiness statement. Otherwise, a defendant may move to dismiss for deprivation of statutory speedy-trial rights.
• Certificate of Compliance (COC): A form signed by the prosecutor attesting that all discoverable material is disclosed after reasonable inquiries. An “illusory” COC is one filed without actual compliance.
• Speedy‐Trial Readiness Statement (SOR): A companion form stating the People are “ready for trial.” It relies on a valid COC; an illusory COC renders the readiness statement invalid.
• Giglio Material: Evidence concerning informant credibility or witness impeachment, named after Giglio v. United States, 405 U.S. 150 (1972).
• BEAST Unit: The Biological, Environmental, and Animal Safety Team within the Suffolk County DA’s office, which centralizes discovery for animal cruelty prosecutions and employs staff “discovery expediters.”

Conclusion

People v. McMahon reaffirms that:

1. Prosecutors must exercise due diligence and make reasonable inquiries before filing CPL 245 Certificates of Compliance—but perfection is not required.
2. Holistic, fact-specific analysis under Bay will determine whether any undisclosed material resulted from an oversight excusable by prompt corrective action.
3. Dismissal under CPL 245.80 remains a remedy of last resort, requiring proportionality review and exhaustion of lesser sanctions.
4. A proper COC preserves the speedy‐trial tolling benefit, ensuring that the People are not unfairly penalized for inadvertent lapses remedied in good faith.

This decision provides important guidance to prosecutors, defense counsel, and trial courts on managing the evolving demands of New York’s stringent discovery and speedy‐trial statutes.