Simi man convicted of girlfriend’s 2020 murder

This case illustrate the devastating outcome of domestic violence, prosecutor says

ON THE STAND—Euren Balbuena testifies in court Nov. 8. Photo courtesy of the Ventura County district attorney’s office

A Simi Valley man accused of murdering his girlfriend, Zaira Patino-Trejo, in 2020 was convicted by a jury Tuesday and will be sentenced Jan. 17.

In addition to first-degree murder, the Ventura County Superior Court jury found Euren Balbuena, 32, guilty of assault with a deadly weapon against the victim’s mother, Ariadna Avetisyan, and battery causing great bodily injury against Patino-Trejo, who lived in Simi Valley.

Patino-Trejo, 31, died from multiple stab wounds, according to the Ventura County medical examiner’s office. The crime occurred in the 5400 block of Los Angeles Avenue at the Woodside Apartments.

In deliberating the case, the jury found two special allegations true: that Balbuena personally used a knife in the killing of Patino-Trejo and he inflicted great bodily injury to Avetisyan. The jury found Balbuena not guilty of attempted murder of Avetisyan.

Supervising Senior Deputy District Attorney Melissa Suttner spoke after successfully prosecuting the case.
“Zaira had a bright future ahead of her, but her life was taken way too soon by a man fueled with rage and jealousy,” Suttner said. “Zaira’s mom witnessed the defendant repeatedly and brutally stab her daughter but was unable to save her.”

“The circumstances of this case are so tragic and illustrate the devastating outcome of domestic violence,” Suttner said.

Deputy Public Defender Tiffany Stone argued in court that Balbuena acted in self defense based on Patino-Trejo’s acts of domestic violence against Balbuena in the past.  

According to the Ventura County district attorney’s office, Balbuena and Patino-Trejo were in the middle of an argument inside their Simi Valley apartment on Feb. 27, 2020.

Aware of the ongoing argument and a history of domestic violence in the relationship, the victim’s mother arrived at the apartment when she could not get in contact with Patino-Trejo, the DA said.

Seeing signs of more abuse on her daughter’s face, the victim’s mother tried to leave with her, but Balbuena wouldn’t let her out of the apartment and instead grabbed a kitchen knife and began swinging it at her.

He slashed her twice in the head before turning and stabbing Patino-Trejo more than 30 times with several knives, eventually killing her, the DA said.
The victim’s mother ran bleeding from the apartment and contacted a bystander who called 911. Simi Valley Police Department officers arrived at the scene and arrested Balbuena, who was still inside the apartment.

Suttner credited SVPD for its outstanding work investigating the case and praised the job done by the jury.

“The jury worked tirelessly and endured weeks of graphic and emotional evidence to reach a verdict in this case and we are grateful to them for their service,” Suttner said.

Patino-Trejo worked as a client associate for Merrill Lynch Wealth Management in Westlake Village.

“Zaira was a valued member of our team and served our clients with great professionalism and care,” a spokesman for the company told the Acorn in 2020.

Police records show that Balbuena was also arrested in January 2020 on suspicion of battery at the same address.

According to Ventura County court records, the January domestic violence incident resulted in a protective order that required Balbuena to stay away from Patino-Trejo. He was also ordered to be monitored by the Ventura County probation department.

In March 2020, he was found in violation of the probation order and $10,000 was added to his bail, according to court records.

SVPD was also called out to a similar incident in 2019 involving Balbuena and Patino-Trejo at a different address, Simi Valley Police Chief Steve Shorts said. There was no arrest at that time.

A search of Los Angeles County Court records showed two cases against Balbuena, both for domestic violence-related incidents.