Failure to Review Criminal Discovery Promptly Is Now a Due-Diligence Problem

For years, some criminal defense attorneys have approached discovery with a practical assumption: if the case is likely to resolve by plea, there is little reason to spend substantial time reviewing discovery early in the case.

New York’s current discovery statute makes that approach increasingly difficult to justify.

Under CPL 245.10, the prosecution generally must provide initial automatic discovery within 20 days after arraignment when the defendant is in custody and within 35 days when the defendant is not in custody. Article 245 does not create an exception for cases that counsel expects will resolve before trial.

More importantly, amendments to CPL 245.50 that became effective in August 2025 now impose a separate deadline on the defense. A challenge to the validity of the prosecution’s Certificate of Compliance (“COC”) generally must be made by motion within 35 days after service of the certificate.

That does not mean the defense has 35 days to review discovery.

The 35-day period is the entire window in which counsel must review the production, identify specific deficiencies, determine whether the COC is inaccurate or incomplete, confer or make good-faith efforts to confer with the prosecution, evaluate whether the issue has been cured, prepare the motion, and file the challenge.

In practical terms, the defense has less than 35 days to complete the substantive discovery review itself.

The statute allows the court to extend the 35-day period for good cause, but the request for an extension must be made before the deadline expires. After the deadline, a challenge may still be permitted where there has been a material change in circumstances, such as belated disclosure, or where the defense could not, with due diligence, have known the specific and particularized facts forming the basis of the challenge earlier. CPL 245.50(4)(c)(i)-(ii).

That language makes timely discovery review critical.

People v. Contreras: Review the Discovery When You Receive It

In People v. Contreras, 89 Misc 3d 1204(A) (Sup. Ct., Bronx County 2026], defense counsel challenged the prosecution’s COCs after expiration of the statutory deadline. The defense argued, among other things, that proper discovery had not been provided.

The court rejected the late challenge. It found no material change in circumstances and concluded that the alleged deficiency could have been discovered earlier through the exercise of due diligence in reviewing the case file.

The court made the obligation explicit:

“The defense had a professional obligation to examine the discovery upon receipt to determine whether it was the correct materials, let alone complete.”

The court further noted that counsel had failed to alert the prosecution to the deficiencies for months. Because the problem could have been identified earlier through a timely review of the discovery, the statutory exceptions did not rescue the untimely challenge.

Trial Courts Are Enforcing the 35-Day Deadline

Contreras is not an isolated warning.

In People v. Sanders, 89 Misc. 3d 1230(A), 2026 N.Y. Slip Op. 51110(U) (Crim. Ct., N.Y. County 2026), the court held that where more than 35 days had passed without a COC challenge or a timely request for an extension, the defense was precluded from challenging the COC unless one of the statutory exceptions could be established.

Similarly, in People v. De Jesus, 89 Misc. 3d 1222(A), 2026 N.Y. Slip Op. 51027(U) (Crim. Ct., N.Y. County 2026, the defense had actually obtained an extension of the COC challenge deadline and still failed to file the motion. The court held that the defense had not complied with CPL 245.50(4)(c) and that any COC challenge was procedurally time-barred absent a qualifying material change in circumstances.

The developing message is straightforward: a discovery issue that could have been identified through a timely review may not become a viable late COC challenge simply because counsel eventually discovers it.

“I Thought the Case Would Plead” Is Not a Discovery Rule

Nothing in CPL Article 245 suspends the discovery timetable because counsel believes a case is likely to resolve.

In fact, the statutory scheme contemplates discovery before disposition. Article 245 imposes automatic discovery obligations early in the case, and CPL 245.25 separately addresses disclosure in connection with guilty pleas. The Legislature did not condition discovery obligations - or the defense’s opportunity to challenge compliance - on whether counsel expects a trial.

A case that appears likely to resolve today may be headed toward hearings or trial tomorrow.

A client may reject an offer. Negotiations may collapse. New information may change the defense position. Counsel may later discover that material identified in the COC was never actually produced.

By then, however, the 35-day challenge period may already have expired.

And the problem is not merely that counsel waited too long to file a motion. Counsel may have waited too long to begin the process necessary to make the motion.

The sequence matters:

• review the discovery;

• compare it against the COC;

• identify specific deficiencies;

• confer with the prosecution;

• determine whether the deficiency has been cured;

• research and analyze the issue;

• prepare the challenge; and

• file within the statutory period.

The defense does not have 35 days to do the first step. It has 35 days to complete the entire process.

Discovery Review Is Now Deadline-Sensitive Work

Receiving discovery is not the same as reviewing it.

A meaningful discovery review should allow counsel to determine whether the production corresponds with the COC, whether identified materials were actually provided, whether obvious categories of automatic discovery appear to be missing, and whether an issue needs to be raised with the prosecution while there is still enough time to preserve a challenge.

CPL 245.50 expressly requires a party who is aware of a potential defect or deficiency concerning a COC to alert the opposing party, and it requires challenges to be made within the statutory period. The statute therefore assumes that someone is examining the production early enough not only to identify the problem, but also to complete the required conferral and motion practice before the deadline.

That has implications beyond trial preparation.

Prompt discovery review is now part of issue preservation.

An attorney may ultimately decide that a discovery deficiency is immaterial, that a COC challenge is unwarranted, or that the case should resolve without litigation over discovery. Those are legal judgments.

But the judgment can only be made if the discovery has first been reviewed—and reviewed early enough to preserve the available options.

The Bottom Line

Under the current CPL 245.50 framework, postponing discovery review because a case is expected to resolve carries procedural risk.

The 35-day deadline is not a 35-day review period. It is the full period for reviewing the production, identifying defects, conferring with the prosecution, determining whether the issue remains unresolved, preparing the motion, and filing the challenge.

A defect that is apparent today may be unavailable as the basis for a COC challenge later if the court concludes that diligent counsel could have identified and raised it within the statutory period.

People v. Contreras makes the point plainly: defense counsel has a professional obligation to examine discovery upon receipt.

For criminal defense practices managing multiple active matters, timely discovery review should therefore be treated as a deadline-sensitive component of case management—not something reserved for cases that appear likely to go to trial.

Just Write Legal, LLC provides criminal discovery review, COC analysis, legal research, motion drafting, and deadline-sensitive issue review for attorneys who need an additional substantive quality-control layer in their practices.