San Diego Man Saw Ex's Engagement Post, Googled 'How to Kill Someone in Self-Defense' Before Allegedly Killing Her Fiancé

Jesse Alvarez, Mario Fierro and Amy Gembara
Jesse Alvarez (left) and the engagement post shared on social media congratulating Mario Fierro and Amy Gembara. Facebook

A San Diego man is accused of stalking his ex-girlfriend for more than a year after a judge rejected her request for a restraining order ― and then killing his ex's fiancé.

Prosecutors say Jesse Alvarez was spurred by jealousy when he carefully planned the fatal shooting of 37-year-old Mario Fierro, a beloved teacher who was engaged to fellow teacher and Alvarez's ex Amy Gembara.

Alvarez was Stalking Gembara Since Their Break-Up, was Triggered After Seeing Her Engagement Post with Fierro

During the trial, prosecutors argued that Alvarez, now 33, was stalking Gembara since their break-up in September 2019, after three years of dating. On the morning of Feb. 1, 2021, Alvarez shot Fierro six times in front of his home as he was preparing to leave for work in the North Park neighborhood of San Diego.

Alvarez was arrested at his home that evening, and later pleaded not guilty to the murder charge, which includes a special circumstance allegation of lying in wait. Alvarez targeted Fierro after he saw a picture of him and Gembara in a social media post by the high school on Dec. 21, 2020, congratulating the couple on their engagement, prosecutors said.

Six weeks after the engagement post, Alvarez drove his brother's car to Fierro's apartment and waited for an hour, confronting him just after 7 a.m. Prosecutors called the shooting an ambush, but Alvarez's defense attorney said he acted in self-defense — that Fierro had assaulted him when all he wanted to do was talk.

Alvarez's Google Searches

Among his Google searches in the days after the engagement post, prosecutors said, were "hire hitman san diego ca," "how to shoot someone in self defense," "how to shoot someone without leaving forensic evidence," "does a phone on airplane mode track GPS location," and "do the police use cellphone GPS data when tracking criminal activity."

One search in particular stood out to investigators: "how to kill your ex's fiancee [sic]." Alvarez also visited websites with names including "How to Commit the Perfect Murder," "16 Steps to Kill Someone and Not Get Caught" and "Leaving an Invisible Trail: How Killers Cover Up Their Crimes," prosecutors said.

Alvarez's Defense Claims He Suffers from Autism, was 'Heartbroken' After Gembara's Engagement

Alvarez also said in court he has autism, which his attorney says makes it difficult to understand social cues. Alvarez's attorney said he was "heartbroken" upon learning Gembara had gotten engaged, NBC reported.

Alvarez also addressed the Google searches, acknowledging that they were "really weird," reported NBC. He further testified that he had fantasized about Fierro's death, but didn't intend to kill him and turned to Google because he didn't have anyone to talk to, according to the outlet.

If Alvarez is convicted of first-degree murder, he faces life in prison.