Possibly, but there is no automatic right to take a police-held sample to a private laboratory or consume part of it without agreement or a court order. Penal Code section 1054.1 requires disclosure of relevant real evidence seized or obtained in the investigation when it is held by the prosecutor or known to be held by investigating agencies. That disclosure rule does not itself decide who may handle or test the physical exhibit. Penal Code section 1054.1.
Identify the sample and the question
Have counsel first confirm that a physical sample remains and identify its package or evidence number, amount, storage location, prior testing or consumption, and current custodian. Separate the sample from the laboratory report: a report may be available even when no usable material remains. State what a second examination is meant to resolve—such as identity, weight, mixture, or handling—and identify a qualified lab and proposed method.
The request should address how the evidence will be inspected, what portion may be taken, whether testing could consume or alter it, how identity and chain of custody will be maintained, and what material will remain for the prosecution. The court order or agreement should set out handling and preservation terms. Do not remove, ship, open, or test a sample yourself.
Use a noticed request and resolve disputes through court
Start with an informal discovery request to the prosecutor identifying the exhibit and proposed access. If the prosecutor has not provided material required by the discovery chapter within 15 days, Penal Code section 1054.5 permits a motion for an enforcement order. The prosecutor must receive notice; the procedure is not a secret, ex parte request asking police to release evidence directly to a private lab. Penal Code section 1054.5.
In Walters v. Superior Court, the evidence was a firearm, not drugs. The court rejected an ex parte order for defense testing of police-held evidence and treated access as a criminal discovery issue involving notice to the prosecution. Prince v. Superior Court allowed testing of a divisible half of a biological sample. In People v. Cooper, a court could require joint testing where one small, undivided blood sample would be consumed. These decisions illustrate why the result depends on quantity, divisibility, and risk to the evidence; applying them to a drug sample is case-specific, not a drug-specific automatic retesting right. Walters; Prince; Cooper.
If the item was seized under a search warrant, Penal Code section 1536 places it in the custody of the officer executing the warrant, subject to the court’s order. That statute does not govern every warrantless seizure. Penal Code section 1536.
Keep trial disclosure separate
If the defense intends to offer test results, a report, or an expert at trial, reciprocal discovery may apply. Sections 1054.3 and 1054.7 address intended defense witnesses, relevant expert statements or reports, scientific results intended to be offered, and disclosure timing. That is not a rule that every private consultation or draft must be disclosed; counsel must assess the actual material and intended use. Penal Code section 1054.3; Penal Code section 1054.7.
The Law Offices of David S. Chesley handles California drug-defense matters. Call (800) 755-5174 to discuss the evidence record and a proposed testing plan.