Prosecutor: Jealous ex-boyfriend killed beloved high school teacher

Posted at 9:49 AM, February 27, 2024

SAN DIEGO (Scripps News San Diego) — Chilling surveillance footage captured the last moments Mario Fierro was alive.

The teacher at Cathedral Catholic High School died after being shot six times in 2021 by his fiancé’s ex-boyfriend, according to prosecutors.

Jesse Alvarez is pictured in court.

Defendant Jesse Alvarez is pictured in court on Feb. 26, 2024. (Scripps News San Diego)

The shooting in North Park, which was captured on multiple cameras with audio, was played in court on the first day of the murder trial for Jesse Alvarez, 33.

After the first shot goes off, screaming is heard before several more gunshots are heard.

“The defendant methodically plotted his execution and part of that planning was to surprise him with it,” prosecutor Ramona McCarthy told the jury in her opening statement.

McCarthy pointed to Alvarez’s Google searches and internet history.

“He started researching how to hire a hit man,” she said.

His Google searches included “how to kill your ex’s fiancée,” “how to shoot someone in self defense” and “does a phone on airplane mode track GPS location.”

Alvarez also read an article entitled ‘how to commit the perfect murder,’ signed up for gun classes, and bought two firearms.

McCarthy said Alvarez stalked his ex-girlfriend Amy Gembara, who also worked as a teacher at Cathedral Catholic High School.

She said he even applied for jobs at her school and showed up outside her classroom after she broke up with him.

Amy Gembara takes the witness stand in the case against Jesse Alvarez,

Amy Gembara takes the witness stand in the case against Jesse Alvarez, who’s accused of gunning down her fiancé, Mario Fierro. (Scripps News San Diego)

Alvarez lost it after seeing a photo of his ex with Fierro, which the school posted online announcing their engagement, McCarthy said.

“From that point forward the defendant methodically planned Mr. Fierro’s execution and why because she was happy. She wasn’t happy with him.”

Gembara told jurors how Alvarez continued to pursue her after the breakup. “Every time I blocked him there would be a new way that would pop up.”

She tried to get a restraining order, but a judge denied her request after Alvarez presented a lengthy counterargument and swore that he wouldn’t contact her anymore.

Defense attorney Kelly Armstrong said Alvarez will testify to tell his side of the story. He said his client is “very autistic.”

“He doesn’t always look at things the way someone who does not suffer from autism looks at life, looks at relationships.”

Armstrong said his client bought two guns, but they weren’t to kill Fierro even though “he was crushed” when he saw the engagement photo online.

“Mr. Alvarez was concerned about the political climate in the United States at that time. You’ll recall there were a lot of riots going on across the U.S. He was worried for his safety.”

Armstrong said when Alvarez showed up outside Fierro’s car, the teacher recognized him and started to hit him.

“Mr. Alvarez will tell you that he backed up several steps and Mr. Fierro kept coming toward him, assaulting him, hitting him.”

He said his client “finally took the gun out and pointed it at Mr. Fierro’s body and said, ‘Stop! Just stop!’ as he kept backing up.”

Alvarez then shot the gun seven times. Six shots hit the schoolteacher in the back, arm, and head.

The trial is expected to last about two weeks. Alvarez has pleaded not guilty and faces life in prison without a chance of parole if convicted.

This story was originally published by Scripps News San Diego, an E.W. Scripps Company.