Federal investigators are actively searching for Matthew Flores Semyonov, a 27-year-old man suspected of murdering his parents, Hector and Larissa Flores, in their Litchfield Park, Arizona, home. Semyonov is currently at large and believed to have fled the United States, with his exact whereabouts unknown. The investigation began on August 4, 2026, when Avondale police officers conducted a welfare check at the family residence following concerns raised by another son who had not heard from his mother in several days. Upon arrival, officers discovered large amounts of blood and evidence of attempted cleanup. Two days later, on August 6, the bodies of Hector, 69, and Larissa, 63, were found buried in the backyard. Hector Flores was an associate professor of management and human resources at Cal Poly Pomona, while Larissa Flores worked for Circle the City, a nonprofit providing healthcare to homeless individuals in Maricopa County. According to police reports, Semyonov had exhibited significant behavioral changes while in college, including becoming less social and making vague threats. He reportedly became upset after learning of his father’s infidelity and his mother’s decision to remain in the marriage. Medical evaluations indicated that Semyonov had been diagnosed with a mental health disorder involving auditory hallucinations. He is wanted on suspicion of first-degree murder, domestic violence, and abandonment or concealment of a dead body. The FBI, U.S. Marshals Service, and Phoenix police homicide detectives are assisting Avondale police in the manhunt. The U.S. Marshals Service is coordinating with federal and international law enforcement partners to locate Semyonov. Individuals with information regarding his location are urged to contact the U.S. Marshals’ 24-hour tip line at 1-877-926-8332 or submit an anonymous tip via the agency’s Tips App or website. The causes and manners of death for the victims remain pending as the Maricopa County Medical Examiner’s Office continues its analysis.