SANTA ANA – A state appeals court on Thursday ordered a new trial for a Santa Ana mother who admitted to drowning her baby daughter in a bathtub.

A panel of California Court of Appeals judges cited a jury-instructions failure in reversing the murder conviction of Lucero Carrera, who in 2015 was sentenced to 25 years to life in prison for killing her two-month-old daughter, Kimberly.

Carrera, who was living with her mother in Santa Ana, had an undisputed history of mental illness, having been diagnosed with bipolar disorder, hospitalized several times and attempted suicide.

On June 29, 2012, while her mother was on a quick trip to a store, Carrera ingested a full bottle of medication, removed Kimberly’s clothes, filled a bathtub, closed the bathroom’s door and held the baby girl under the water.

Carrera’s mother returned to find Kimberly’s lifeless body floating face-down in the bathtub. Carrera told police that she drowned her daughter so that the girl “wouldn’t suffer what I suffered.”

Carrera’s attorney, Deputy Public Defender Kira Rubin, asked jurors to focus on her client’s mental health: Carrera cycled through manic and depressive states, had been persuaded by family to not give the girl up for adoption despite her being worried she wouldn’t be able to care for the girl, and had stopped taking her medication soon after Kimberly’s birth.

Jurors found Carrera guilty of first-degree murder, and determined that she was legally sane at the time of the killing.

In overturning the verdict, the justices wrote that jurors should have been told that they could “consider evidence of Carrera’s mental impairments to determine whether she had actually formed the specific intent required for premeditated murder.”

At one point early in the jury’s deliberations, the justices noted, jurors specifically asked whether they could consider her state of mind during the crime. The jurors also asked for testimony from a paramedic about Carrera’s demeanor immediately after the drowning be read back to them.

“In our view, simply telling the jury Carrera’s state of mind was an issue to be considered was not enough,” the appeals court justices wrote in their opinion. “The jury’s questions, their request for readback and their verdict immediately after the readback all demonstrate Carrera’s mental impairment evidence was critical, and strongly suggest the jury did not know how to properly consider it.”

The appeals court justices wrote that the judge who presided over the trial – Orange County Superior Court Judge Thomas M. Goethals – was not to blame for the jury-instruction issues. Instead, Rubin should have requested the specific instructions, the panel wrote.

“We simply have no confidence in the outcome of this trial,” the appeals court justices wrote.

Rubin could not be reached for comment.

“The Orange County District Attorney’s Office is reviewing options, which could include an appeal to the state Supreme Court,” spokeswoman Michelle Van Der Linden said.