What is the burden of proving a conspiracy to sell cocaine?

There is no question that the government proved the existence of a conspiracy to sell cocaine: an undercover officer made numerous purchases of cocaine from the conspirators. "Once the existence of a conspiracy is shown, the government need only prove a slight connection between the defendant and the conspiracy." United States v. Matta-Ballesteros, 71 F.3d 754, 765 (9th Cir.1995). If that burden is met, a conspirator is liable for all foreseeable substantive offenses committed in furtherance of the conspiracy. Id.