Maryland law requires the police to secure the alleged illegal drug until the drug is tested by a chemist approved by the State. To prove that the substance was properly secured, the police prepare a statement showing the “chain of physical custody”.
The requirements are minimal. The document needs to show, in standard cases, that the arresting officer placed the substance into a package that the officer then sealed and then that the chemist removed the substance from the sealed package.
The chemist then completes a form showing the results of the test or tests performed.
To preserve the right of the defendant to cross-examine those in the chain, including the chemist, the defendant must file a written demand in court at least five days prior to the trial.
The courts have ruled that defendants, upon request, are entitled to review the laboratory notes of the chemist. Also, the State’s failure to produce the witnesses in the chain can render inadmissible the drug or the test results.