What is a Kellett motion for my criminal case?

The key case on point is Kellett v. Superior Court (1966) 63 Cal.2d 822 (Kellett). It set forth the fundamental standards that we must follow.

Kellett established a standard for determining when a successive prosecution is barred that remains viable today. "When . . . the prosecution is or should be aware of more than one offense in which the same act or course of conduct plays a significant part, all such offenses must be prosecuted in a single proceeding unless joinder is prohibited or severance permitted for good cause. Failure to unite all such offenses will result in a bar to subsequent prosecution of any offense omitted if the initial proceedings culminate in either acquittal or conviction and sentence." In sum, the test contains a mental standard, a physical standard, and an exception-providing legal standard. If the prosecution negligently, recklessly, knowingly, or purposefully (the mental standard) elects not to prosecute all offenses arising out events in which the same act or course of conduct (the physical standard) plays a significant part, then bringing the omitted charges later is prohibited unless there was a statutory reason (the exception-providing legal standard) that the charges could not all be brought in the first instance.

While this provision addresses both multiple punishment and multiple prosecution, these “separate concerns have different purposes and different rules of prohibition.” (People v. Valli (2010) 187 Cal.App.4th 786, 794 (Valli).) “The purpose of the protection against multiple punishment is to insure that the defendant's punishment will be commensurate with his criminal liability.” Whether Kellett applies must be determined on a case-by-case basis.” (Valli, supra, 187 Cal.App.4th at p. 797.) In making this determination, we consider the totality of the facts and whether separate proofs were required for the different offenses. (Valli, supra, at p. 798, citing People v. Flint (1975) 51 Cal.App.3d 333, 337-338.) “More specifically, if the evidence needed to prove one offense necessarily supplies proof of the other, we concluded that the two offenses must be prosecuted together, in the interests of preventing needless harassment and waste of public funds. [Citation.]” (People v. Hurtado (1977) 67 Cal.App.3d 633, 636.)