TUSTIN, CA — A 47-year-old Hawthorne man accused of fatally shooting his ex-girlfriend outside her workplace was arrested Saturday at the U.S.-Mexico border after fleeing the country following the killing, Tustin police announced.
Juan Marquez allegedly waited near Sandra Fernandez’s workplace Thursday evening before shooting the 42-year-old Anaheim mother of three to death on Yorba Street. The arrest comes as investigators piece together what police describe as a calculated attack that left Fernandez dead just steps from her vehicle after completing job training at a position she had started only a month earlier. Marquez fled across the border immediately after the shooting but was detained by U.S. Customs and Border Protection agents when he attempted to return to the United States.
Officers responded to multiple calls about gunshots near the intersection of Yorba Street and Medford Avenue just after 6 p.m. Thursday, May 14. They found Fernandez lying behind a small white SUV, suffering from fatal gunshot wounds. She was pronounced dead at the scene. Witnesses reported seeing a man dressed in black clothing fleeing the area in a dark-colored older model sedan immediately after the shooting. The investigation revealed that Marquez had positioned himself near Fernandez’s workplace at Families Together of Orange County, where she had been completing training for her new position. According to police, Fernandez was walking to her car when the attack occurred.
Tustin Police Department investigators quickly identified Marquez as a suspect through their investigation, though officials have not disclosed the specific evidence that led to his identification. After determining Marquez’s involvement in the shooting, detectives learned he had crossed into Mexico through the San Ysidro Port of Entry shortly after the killing. Police obtained an arrest warrant for Marquez on Saturday, May 16, and coordinated with federal authorities to apprehend him upon his return. U.S. Customs and Border Protection agents detained Marquez Saturday afternoon as he attempted to re-enter the United States through the border checkpoint. The timing of his attempted return and the circumstances surrounding his decision to come back remain unclear.
Fernandez was described by colleagues and family as a devoted single mother to three children ranging in age from 5 to 21 years old. She had recently started working at Families Together of Orange County, a nonprofit organization, and was still in her training period when she was killed. Cassie Rossel, identified as Fernandez’s coworker, told KTLA that despite working there for less than a month, Fernandez had already begun forming strong relationships and making a positive impact. The victim’s family has set up a GoFundMe account to help cover funeral expenses as they cope with the sudden loss. Some news reports identified the victim as Sandra Rodriguez, though police officially named her as Sandra Fernandez in their statements.
Tustin police detectives took Marquez into custody from federal agents and transported him to Orange County Jail, where he was booked just before 1 a.m. Sunday, May 17. He faces a murder charge and is being held without bail pending his court appearance. The case highlights the challenges law enforcement faces when suspects flee across international borders, requiring coordination between local police, federal immigration authorities, and border security agencies. Police emphasized that the shooting appears to be an isolated incident between former romantic partners and poses no ongoing threat to the public. The investigation into the specific circumstances of the relationship between Marquez and Fernandez, including any history of domestic violence, continues.
The deadly shooting occurred in a residential area of Tustin near the victim’s workplace, sending shockwaves through the community and her family. Fernandez’s death represents another tragic case of domestic violence that escalated to murder, leaving three children without their mother. Authorities have not released details about the weapon used or whether Marquez had any prior criminal history. The case also demonstrates the effectiveness of coordination between local law enforcement and federal border agencies in apprehending suspects who attempt to evade justice by crossing international boundaries.
Marquez remains in Orange County Jail as prosecutors prepare their case against him. His first court appearance has not yet been scheduled, and it was not immediately clear whether he has retained legal representation. The investigation continues as detectives work to build their case for prosecution while Fernandez’s family and community mourn the loss of a woman described as making a positive impact wherever she went.
