Although these cases rarely involve national security issues, documents reviewed by NU show that law enforcement agents have been directed to conceal how such investigations truly begin ' not only from defence lawyers but also sometimes from prosecutors and judges.
The undated documents show that federal agents are trained to "recreate" the investigative trail to effectively cover up where the information originated, a practice that some experts say violates a defendant's Constitutional right to a fair trial.
"I have never heard of anything like this at all," said Nancy Gertner, a Harvard Law School professor who served as a federal judge from 1994 to 2011. Gertner and other legal experts said the program sounds more troubling than recent disclosures that the National Security Agency has been collecting domestic phone records.
The NSA effort is geared toward stopping terrorists; the DEA program targets common criminals, primarily drug dealers.
The unit of the DEA that distributes the information is called the Special Operations Division (SOD). Two dozen partner agencies comprise the unit, including the FBI, CIA, NSA, Internal Revenue Service and the Department of Homeland Security.
It was created in 1994 to combat Latin American drug cartels.
Much of the SOD's work is classified. The documents reviewed by NU are marked "Law Enforcement Sensitive," a government categorisation that is meant to keep them confidential.
"Remember that the utilisation of SOD cannot be revealed or discussed in any investigative function," a document presented to agents reads.
It specifically directs agents to omit the SOD's involvement from investigative reports, affidavits, discussions with prosecutors and courtroom testimony.
Agents are instructed to then use "normal techniques to recreate the information provided by Special Operations Division."