Some members of the Colorado Supreme Court appeared uncomfortable on Tuesday with allowing a criminal defendant to stand trial a second time after a Larimer County jury signaled it was deadlocked on some counts but found him not guilty of the more serious charges.

Omar Alexander Mena stood trial last summer for three counts of sexual assault. After the evidence concluded, the prosecution asked for the jury to also be instructed that it could find Mena guilty of a lesser offense of attempted sex assault for each charge. Over the defense’s objection, District Court Judge Sarah B. Cure gave jurors the option of finding Mena guilty of either assault or of attempted assault for each count, or not guilty for both.

On the second day of deliberations, the jury told Cure they had unanimously agreed on the “primary” charges but not the “secondary” ones. After Cure asked jurors to clarify what they meant and sent them home for the night, the jury indicated the next day that it reached a unanimous verdict on the assault charges, but not the attempt charges.

The defense asked Cure to provide the jurors with a modified form to enter their unanimous verdict on the assault charges. Given the jury’s instructions, an acquittal was the only logical outcome. But Cure declined, and instead declared a mistrial for all counts.

“I am concerned here on whether the focus was on doing justice for Mr. Mena or making sure the prosecution didn’t lose. And that’s troubling to me,” said Justice Richard L. Gabriel during oral arguments.

“Even if the jury has said, ‘All 12 of us have found the defendant not guilty of the charged offenses,'” added Justice Carlos A. Samour Jr., “even in that case, you don’t think the double jeopardy clause should warrant the judge giving a modified verdict form?”

The constitutional protection against double jeopardy prevents the prosecution from retrying a defendant who has previously been acquitted for the same offense.

In the 2008 decision of People v. Richardson, the Supreme Court held that a trial judge does not have to accept a partial verdict from jurors when they have indicated a decision on some charges but are deadlocked on others. Then-Justice Alex J. Martinez dissented, warning that jurors would have no way to register an acquittal and the defendant would be unaware he was being placed in jeopardy a second time.

“To protect against the realistic danger of these future double jeopardy violations, the better procedure would provide an opportunity for the jury to render a partial verdict and thereby shield the defendant from retrial on offenses for which he was in actuality acquitted,” Martinez wrote.

“I’m troubled that the court didn’t allow a verdict,” Gabriel told Mena’s lawyer. But in light of Richardson, “I don’t know of any law that required the court to do it. There’s a lot of law that says partial verdicts should not be allowed.”

Defense attorney Cassandra P. Monahan noted Mena’s case was different from Richardson’s, and the jury had given a more explicit description of where it stood. Because of the options on the verdict form, it was evident that jurors had not found him guilty of sexual assault, and were only conflicted about the lesser attempt charges.

“We had a verdict,” she said. “The trial court’s actions here prevented that verdict from being effectuated.”

Deputy District Attorney Russell Connelly argued that allowing judges to accept partial verdicts in cases like Mena’s would be difficult without opening the door to other scenarios.

“Other than the fact that you wouldn’t get a second bite at the apple in trying the charged offenses,” asked Samour, “what concerns (does the prosecution) have?”

“The jury, they were obviously deliberating the lesser (offenses),” said Connelly. “Maybe some jurors concluded they believed that defendant was guilty as charged, but they were willing to move on to consider the lesser (offenses) in the interest of returning a verdict.”

“That’s not what the note said,” replied Samour. “The note said, ‘We’re unanimous on the charged offenses’” for assault.

Connelly suggested that the Supreme Court hold that trial judges do not act unreasonably by declining to allow jurors to return a partial verdict. But the roadblock there, observed Chief Justice Monica M. Márquez, may be the Constitution.

“It seems, I think, everybody would agree that generally it’s up to the court’s discretion to issue a modified verdict form,” she said. “But isn’t that discretion constrained by the double jeopardy clause?”

The case is People v. Mena.