Yes, each element of a tax crime must be proved beyond a reasonable doubt just like other crimes. According to the Ninth Circuit, the evidence must be reviewed “in the light most favorable to the prosecution to determine whether any rational fact finder could have found the essential elements of the offense beyond a reasonable doubt.” U.S. v. Marashi, 913 F.2d 724, 735 (9th Cir. 1990).
For example, each of the three elements of tax evasion must be proved beyond a reasonable doubt: that (i) the taxpayer attempted to evade or defeat a tax or the payment of a tax; (ii) the taxpayer had additional tax due and owning, and (iii) he acted willfully in his attempt.