Scholarship has long recognized a disparity between the discovery rights afforded to civil litigants and those afforded to criminal defendants. The consensus is that this disparity is caused by resource constraints and limited access to the prosecutorial file. This Article challenges that conception, contending that criminal defendants are in fact structurally precluded from conducting any formal investigation. Merely entitled to disclosures of the State's evidence, a criminal defendant must rely on the fruits of the opponent's investigation to somehow suggest a counter-narrative. This dynamic is inconsistent with the design of the adversarial system and results in a failure to engage in adequate pretrial testing. This Article recasts a criminal defendant as an essential party to a criminal investigation who should have the pretrial power to compel information from multiple sources. Certainly, greater access to the prosecutorial file and more resources will mitigate discovery deprivations that currently plague criminal defendants. But without extending a criminal defendant the power to direct an independent and formal investigation, adequate pretrial testing cannot occur. Evaluating the investigative tools that should be extended to a criminal defendant, the Article utilizes a case study to ascertain how the application of these tools might affect a pretrial investigation. Finally, the Article surveys and responds to policy arguments against permitting the participation of criminal defendants in criminal investigations.