Supreme Court of New Mexico Reverses Defendant’s Murder Conviction Because Prosecutor Improperly Asked Why Her Six Month Old Daughter Tested Positive for Meth

A classic rule of character evidence is the “mercy rule,” pursuant to which evidence of a criminal defendant’s bad character can only be introduced after the defendant has presented evidence of her good character. And this “door opening” procedure ended up being a problem for the State in the appeal of Cristal Cardenas based upon the Supreme Court of New Mexico finding that bad character evidence crept in despite her keeping the door shut.

In State v. Cardenas, 2025 WL 925789 (N.M. 2025), Cristal Cardenas appealed her convictions for her alleged role in the 2018 murder-for-hire plot of her ex-boyfriend. At trial, the prosecutor had asked Cardenas on cross-examination why her six month old child tested positive for methamphetamine. On appeal, the Supreme Court of New Mexico found this was reversible error, concluding as follows:

Under Rule 11-404(A)(2)(a), a criminal defendant “may offer evidence of the defendant’s pertinent [character] trait.”…But if a defendant does so, a prosecutor may offer evidence to rebut evidence of the pertinent character trait….

The classic way of offering character evidence involves calling a “defense character witness” who testifies to the defendant’s reputation or provides an opinion on a defendant’s pertinent trait….However, defendant-witnesses can also address their own character by testifying beyond background information and presenting self-portraits as persons whose experience, personality, philosophy, and disposition make it less likely that they committed the crime. See id. at 703-04. In such cases, “the defendant personally opens the door to … counterattacks” on character, allowing the State to offer evidence to rebut the image the defendant has created. Id. The State claims the latter method of introducing character evidence is what happened in this case. 

At trial, the State argued that Defendant offered evidence of three character traits: that she is a “law-abiding citizen,” “peaceful,” and “a good mother.” Our review of the record indicates that Defendant did not offer, or attempt to offer, proof of these character traits on direct examination. In other words, there was no such testimony to rebut.

Defendant did not testify that she was a law-abiding citizen. The testimony in that broad ambit was that she was not prohibited from exercising her Second Amendment rights and did not have a conviction for a felony, a crime of violence, or domestic violence. Defendant’s specific statements do not constitute evidence for her character as a generally law-abiding citizen….

The State similarly overreaches to contend that Defendant testified that she had a character trait of peacefulness. Defendant stated that she was not angry with the judge adjudicating her custody issues and that she “just wanted everything to go right for [her] daughter[, Y.C.].” She stated that she “always encouraged [her daughter, Y.C.,] to have visits with her dad” despite parenting difficulties, that she never had a gun, and that she did not have a conviction for a felony, a crime of violence, or domestic violence. This testimony does not equate to Defendant testifying that she had a peaceful character. Moreover, even if she had, the State’s inquiry into A.F.’s positive methamphetamine test would be off-target and inadmissible as a rebuttal.

Finally, we conclude that Defendant did not testify that she had the specific character trait of being a good mother. In addition to stating that she wanted everything to go well for her daughter, Y.C., Defendant testified that she planned to transfer ownership of their house to Y.C. and that she put child support payments into a savings account for Y.C. and encouraged Y.C. to have visits with her father, Cabral. This does not amount to a proof or attempted proof of a character trait of being a good mother. And there is no suggestion in this case that Defendant was responsible for A.F.’s exposure to methamphetamine, so we are not persuaded that the inquiry into A.F.’s positive test would be admissible to rebut evidence that she had the character trait of a good mother had there been such evidence.

When as in this case the defendant-witness testimony is focused on background information and facts relevant to the charged crime, no “door” is opened to an attack on character….Only if the defendant-witness “ranges beyond these basic [background and relevant] facts” to “personally” self-identify to a jury as the kind of person who would not engage in the charged crime does the character-evidence “door” open. Id. Accordingly, we conclude that it was an abuse of the district court’s discretion to allow the inquiry into the evidence under Rule 11-404(A)(2)(a) because Defendant did not personally open the door to evidence of the specific character traits of being law-abiding, peaceful, or a good mother.

-CM