The Colorado Supreme Court decided on Monday that no specific procedure is required to designate a witness as an expert at trial, and the fact that a trial judge neglected to do so in front of the jury did not warrant reversal of a man’s murder conviction.

Denver jurors convicted Pete Paul Martinez of stabbing 77-year-old Lewis Easterday to death near Cheesman Park in 2016. Martinez admitted to the crime, but asserted he was not guilty by reason of insanity, insisting god had guided his actions. A court-appointed psychologist evaluated Martinez and found him sane.

But the Court of Appeals ordered a new trial for Martinez because of an apparent oversight by the trial judge and the parties. In contrast to the typical practice in Colorado — and in contrast to how the other expert witnesses in Martinez’s case were handled — the prosecution did not offer the psychologist as an expert, nor did the judge accept him as such in front of the jury.

The Supreme Court disagreed that the rules of evidence or its prior precedent required a specific sequence of events to make the testimony valid. Justice Richard L. Gabriel, in the court’s Nov. 4 opinion, noted everyone in Martinez’s case had proceeded with the understanding that the witness was an expert.

“In so concluding, we hasten to add that a formal offer and acceptance of an expert are not prohibited, either. Indeed, it is often good practice for a party to tender an expert in a particular field and for the trial court to make findings, whether before or during trial, as to that expert’s qualifications and the proper scope of the expert’s testimony,” Gabriel wrote.

Yet, “(w)e perceive no reason to dictate a procedure that trial judges and lawyers must follow in all circumstances.”

In convicting Martinez, jurors signaled they believed psychologist Charles Harrison’s testimony that Martinez was sane at the time he killed Easterday. Under the rules of evidence, a witness who is “qualified as an expert” may offer their opinions, with trial judges acting as gatekeepers for reliability. But there is no rule requiring the specific act of offering a witness as an expert and the judge accepting them as such in front of the jury.

By 2-1, a Court of Appeals panel believed District Court Judge A. Bruce Jones’ failure to do so was worthy of reversal, given how important Harrison’s opinions were to the case.

“Dr. Harrison’s testimony was inadmissible because it was expert evidence and the trial court did not determine that he was an expert witness qualified to give expert testimony and did not make specific findings supporting such a determination,” wrote Judge Anthony J. Navarro for himself and Judge Timothy J. Schutz.

Judge Ted C. Tow III dissented, noting the parties had treated Harrison as an expert all along — and even called him an “expert” when speaking during trial. Tow added that he believed the defense’s failure to object was purposeful, meaning Martinez had given up his right to challenge the alleged error on appeal.

At the Supreme Court, the prosecution noted Martinez’s case was an outlier, as parties typically follow the formal protocol. 

“Assuming there is an error, it’s a procedural step,” said Senior Assistant Attorney General William G. Kozeliski during oral arguments. “It’s not that the testimony is inadmissible. It’s that you didn’t do this extra step.”

Justice Carlos A. Samour Jr., a former trial judge, explained there was a reason for parties to formally offer witnesses as experts.

“That’s because the prosecutor is presenting the testimony. I get that the court appointed the witness. But it’s the prosecutor calling the witness. It’s the prosecutor asking the jury to believe that testimony,” he said.

Although Martinez’s lawyer agreed the usual practice for qualifying experts is essential to informing jurors about how to use opinion testimony, Justice Brian D. Boatright wondered why reversing Martinez’s murder conviction was appropriate.

“If we affirm the Court of Appeals and it goes back for a new trial, other than the ‘Your honor, I offer Dr. Harrison as an expert in forensic psychology’ and the court says, ‘So admitted,’ what will be different?” he asked.

Gabriel, in the Supreme Court’s opinion, noted that unlike other cases questioning the scope of an expert’s testimony, Harrison’s statements did not change because the parties neglected to have him designated as an expert in front of the jury. According to the rules of evidence, he reasoned, a witness is qualified as an expert because of their knowledge or skills, not because of a trial judge’s actions.

“In reaching our conclusion in this case, we recognize that for many trial judges and lawyers, the practice of having a party formally tender and the court formally accept an expert has become routine, and we do not intend to suggest that this procedure is categorically improper,” Gabriel wrote.

He added that parties are still required to lay the foundation for an expert’s testimony and judges must appropriately screen it for reliability.

The Supreme Court returned Martinez’s case to the Court of Appeals to consider his other claims.

The case is People v. Martinez.