However, a trial court is under an obligation to instruct the jury properly, People v. Alvarez, 187 Colo. 290, 530 P.2d 506 (1975), and a failure to do so as to every element of a crime charged is plain error. People v. Butcher, 180 Colo. 429, 506 P.2d 362 (1973). Under the plain error standard, applicable here, we must review the defendant's assignment of error to determine whether his substantial rights were seriously affected.
This is not a case of an obvious instance of plain error, such as the failure to instruct the jury on one of the essential elements of the crime charged. People v. Butcher, 180 Colo. 429, 506 P.2d 362 (1973). In such a case, the failure to object to the inadequate instructions can serve no strategic purpose.
It is therefore necessary that the specific ulterior crime be clearly and accurately defined in order to determine if the defendant's intent was that proscribed by the burglary statute. People v. Archuleta, 180 Colo. 156, 503 P.2d 346; People v. Butcher, 180 Colo. 429, 506 P.2d 362. Where, as in Archuleta and Butcher, the ulterior crime was theft, and the theft instruction given by the court was prejudicially erroneous, we have held that the defendant's conviction for burglary must also be reversed. The question, therefore, is whether the sexual imposition instruction constituted prejudicial error requiring reversal of the burglary conviction.
[5] The intent to permanently deprive another of the use and benefit of his property is a material element of the crime of theft. People v. Butcher, 180 Colo. 429, 506 P.2d 362 (1973). The defendant argues that the trial court erred in submitting Instruction No. 2 to the jury in that this instruction, which set forth the material allegations of the charge against the defendant, failed to inform the jury of this intent element.
The jury is apprised of the requirements as to the proof of the several elements of the offense charged through the court's instructions. See People v. Butcher, 180 Colo. 429, 506 P.2d 362. [6,7] Where, as here, the offense charged may be committed in alternative ways, the defendant may require the prosecution to state the particular manner in which he committed the offense by filing a motion for a bill of particulars.