Irving’s contention has merit. First, we note that it does not appear that this issue was raised below; thus, we review only for plain error. Second, the overt act requirement is not a part of the “corpus delicti” of conspiracy. The term, “corpus delicti,” refers to the “body, substance or foundation of the crime.” Black’s Law DICTIONARY 344 (6th ed.1990). The substance of the crime of conspiracy is knowing participation in an agreement to accomplish an unlawful act; the requirement of an overt act is merely an evidentiary prophylactic. See D.C. Code § 22-105a (1989) (providing for punishment of persons who “conspire” in subsection (a), but, in subsection (b), prohibiting conviction unless an overt act is alleged and proved); Bellanger v. United States, 548 A.2d 501, 502-03 (D.C. 1988) (<HOLDING>). Thus, the rule in Opper has no application
holding criminal conspiracy is sustained where the commonwealth establishes the defendant entered into an agreement to commit or aid in an unlawful act with another person with a shared criminal intent and an overt act was done in furtherance of the conspiracy a coconspirator may commit the overt act and conspirators are liable for acts of the coconspirators committed in furtherance of the conspiracy holding proof of an overt act is not required to establish a violation of  846 holding that proof of overt act is not required to support admission of evidence of statement of coconspirator during course of conspiracy holding that proof of an overt act is not required in a  846 conspiracy holding that an 18 usc  1956h conspiracy does not require proof of an overt act