What is the test for simple possession of a controlled substance?

First, defendant challenges the sufficiency of the evidence to prove that he was in possession of the controlled substances or that he knew the substances found in his office were in fact illegal controlled substances. "The essential elements of unlawful possession of a controlled substance are 'dominion and control of the substance in a quantity usable for consumption or sale, with knowledge of its presence and of its restricted dangerous drug character. Each of these elements may be established circumstantially.' [Citations.]" (People v. Martin (2001) 25 Cal.4th 1180, 1184.) Simple possession is "'illegal without regard to the specific intent in possessing the substance.' [Citation.] Although the possessor's knowledge of the presence of the controlled substance and its nature as a restricted dangerous drug must be shown, no further showing of a subjective mental state is required. [Citation.]" (Id. at pp. 1184-1185, fn. omitted.)

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