SAN DIEGO (KGTV) — The man convicted of killing a Cathedral Catholic High School teacher will spend the rest of his life in prison. On Wednesday afternoon, a judge sentenced Jesse Alvarez to life in prison, without the possibility of parole, for the murder of Mario Fierro. Alvarez shot and killed Fierro outside his North Park home in 2021, after finding out that Fierro was engaged to his ex-girlfriend, Amy Gembara.