State v. Wallin, 366 P.3d 651

Defendant Bernard Wallin was convicted of 1 count of rape, 3 counts of aggravated criminal sodomy, and 2 counts of aggravated sexual battery involving an adult victim, M.J., who has developmental disabilities.
Victim M.J. testified and guardian Margaret Kilpatrick described M.J. as developmentally equivalent to a 4–6 year old, unable to sequence events, read, or understand how a baby is made, and easily compliant with adults.
Wallin gave a recorded interview and a written statement admitting sexual contact with M.J. and R.K., asserting the acts were consensual; he also in testimony described M.J. as having very low cognitive ability.
The jury acquitted Wallin on charges involving R.K. but convicted on the counts involving M.J., finding M.J. incapable of consenting due to mental deficiency or disease and that Wallin knew or should have known of that incapacity.
At trial the State presented no expert medical or psychological testimony about M.J.’s capacity; it relied on lay testimony (guardian, victim testimony, defendant’s statements) and the jury’s observation of M.J.’s demeanor.
Wallin appealed arguing (1) insufficient evidence to prove incapacity without expert testimony and (2) the court erred by giving a juror-misconduct admonition after closing arguments that referenced mistrial expense.

Issue	Plaintiff's Argument (State)	Defendant's Argument (Wallin)	Held
Sufficiency: whether victim’s incapacity to consent due to mental deficiency/disease may be proved without expert testimony	Lay evidence and jury observation can prove incapacity; expert testimony may help but is not required in every case	Expert medical testimony was required to prove M.J. was medically incapable of forming consent	Held: Expert testimony is not always required; here lay testimony and victim demeanor sufficed to permit a rational juror to find M.J. incapable of consenting
Juror-misconduct admonition: whether giving an Allen-type admonition after closing coerced verdict or was erroneous	Court’s admonition (warning jurors that misconduct could cause mistrial and expense) is a proper warning to prevent misconduct and was legally accurate	Admonition was an Allen-type coercive instruction referencing mistrial expense and thus prejudicial, especially given timing (after closing)	Held: No reversible error. Instruction similar to PIK Civ. 4th 101.12 was proper; even if timing was suboptimal, defendant did not show prejudice or coercion

State v. Greene, 299 Kan. 1087 (explains consent test: understanding nature and consequences and right to refuse)
State v. Williams, 299 Kan. 509 (standard for sufficiency review: view evidence in light most favorable to prosecution)
State v. Juarez, 19 Kan. App. 2d 37 (jury may evaluate capacity, consider expert testimony if presented)
State v. Salts, 288 Kan. 263 (disapproved Allen‑type language referencing burden of retrial)
State v. Tahah, 302 Kan. 783 (distinguished preliminary juror misconduct admonitions from impermissible Allen instructions)
State v. Papen, 274 Kan. 149 (expert testimony unnecessary when jurors’ common experience allows conclusions)
State v. Gaona, 293 Kan. 930 (standards for admissibility and helpfulness of expert testimony)