A more thorough explanation:

Definition: A sham prosecution is a criminal proceeding that appears to be prosecuted by another sovereignty but is actually controlled by the sovereignty that already prosecuted the defendant for the same crime. It seeks to circumvent a defendant's double-jeopardy protection.

Examples:

• If a defendant was first tried in federal court and acquitted, that fact would not forbid the state authorities from prosecuting the defendant in state court. However, if the state-court prosecution is completely dominated or manipulated by the federal authorities that already prosecuted the defendant, so that the state-court proceeding is merely a tool of the federal authorities, it will not withstand a double-jeopardy challenge.
• A person is charged with a crime in one state and acquitted. The same person is then charged with the same crime in another state, but the second state's prosecution is controlled by the first state's authorities. This is an example of a sham prosecution.

The examples illustrate how a sham prosecution seeks to bypass a defendant's double-jeopardy protection by appearing to be prosecuted by another sovereignty, but is actually controlled by the sovereignty that already prosecuted the defendant for the same crime. It is a misuse of the dual-sovereignty doctrine and violates a defendant's constitutional rights.