Lopez v. People.

2026 CO 23. No. 24SC244.  Evidence—Opening the Door Doctrine—Admissibility of Expert Witness Testimony—Expert Coaching Testimony—CRE 608(a)—CRE 702—Golob v. People—People v. Snook—People v. Gaffney—People v. Fasy—Venalonzo v. People.

April 13, 2026

In this child sexual assault case, the district court admitted expert testimony from a forensic interviewer who, in response to a juror’s question, stated that she observed no signs indicative of coaching during her interviews with the child victims. Lopez appealed, arguing that the expert’s testimony was effectively an opinion on the child victims’ truthfulness on a particular occasion, which is inadmissible. A split division of the court of appeals agreed with Lopez that the expert’s response to the juror’s question was inadmissible, reasoning that an expert witness may not testify about the lack of indicia of coaching during a child victim’s interview because such testimony is analogous to an improper opinion about another witness’s truthfulness on a particular occasion. But the division nevertheless upheld the trial court’s ruling under the opening the door doctrine. It determined that the defense had opened the door to the otherwise inadmissible testimony by persistently advancing the theory at trial that the children’s maternal grandmother wanted to keep custody of them and had therefore coached them or otherwise influenced them to fabricate the allegations or form false memories of abuse.

Assuming, without deciding, that the testimony at issue was inadmissible, the court held that the defense opened the door to it by repeatedly suggesting to the jury—through both the introduction of evidence and the presentation of argument—that the children had been coached or otherwise improperly influenced by their maternal grandmother because she wanted to maintain custody of them.

The court therefore affirmed the division’s judgment.