Iowa Code § 814.28: General verdicts.

When the prosecution relies on multiple or alternative theories to prove the commission of a public offense, a jury may return a general verdict. If the jury returns a general verdict, an appellate court shall not set aside or reverse such a verdict on the basis of a defective or insufficient theory if one or more of the theories presented and described in the complaint, information, indictment, or jury instruction is sufficient to sustain the verdict on at least one count.