Bartlett was serving a life sentence for failing to re-register as a sex offender after his parole for the sex offense had expired. He testified that he did not know that the duty to register was a lifetime requirement, and thought it ended when his parole ended. The jury was instructed that it was not required that the jury find that Bartlett had knowledge of the duty to register. During deliberations, the jury asked the court to elaborate on the meaning of the word “wilfully” as used in the instructions. The court reiterated that actual knowledge is not an element of the offense. Barlett filed a petition for habeas corpus relief. The appellate court here granted relief. Lambert v. California required the state to prove that Bartlett knew of his lifelong duty to register as a sex offender, and therefore the instruction was erroneous. The error clearly was prejudicial, as evidenced by the jury’s question regarding wilfullness.