Hector Flores taught business students, while Larissa Flores treated patients before their deaths triggered an international fugitive investigation.
LITCHFIELD PARK, Ariz. — Before their names appeared in reports about graves behind a suburban Arizona home, Hector and Larissa Flores were known through decades of work in classrooms, business and health care. Hector taught management at a California university. Larissa cared for patients as a psychiatric nurse practitioner. Their professional lives became part of the public record only after police identified them as the couple found buried behind their Litchfield Park residence.
Their deaths have left two investigations moving on different tracks: Avondale police are examining the killings, while the U.S. Marshals Service is leading an international search for the couple’s 27-year-old son, Matthew Christopher Flores Semyonov. Federal authorities allege that Flores Semyonov killed his parents, concealed their remains and fled the United States. He remains wanted on a federal unlawful-flight charge and on state allegations that include first-degree murder.
Hector Flores, 69, was an associate professor in the Department of Management and Human Resources at California State Polytechnic University, Pomona. University officials said he joined Cal Poly Pomona in fall 2015 after a professional career that included years in private industry. He earned a doctorate in strategic management from the University of Massachusetts Amherst and an MBA from Columbia University, and he taught subjects including strategic management, senior projects and internships.
His role at the university went beyond the classroom. Cal Poly Pomona said Hector Flores conducted research in strategic management and served on academic and departmental committees. He participated in faculty governance, including service in the Academic Senate, and was involved with the California Faculty Association on campus. In its statement after his death, the university emphasized his work with students and his contributions to faculty life, presenting a portrait of an educator whose career crossed both corporate management and higher education.
Larissa Flores, 63, worked in a different field but also in a service profession. She was a psychiatric nurse practitioner affiliated with Circle the City, a Phoenix-area organization that provides health care to people experiencing homelessness. The organization said she cared deeply about patients and approached them with compassion, warmth and dignity. Coworkers described her as a cherished member of their organization whose absence would be felt by both staff and people receiving care.
The circumstances that brought those tributes came into focus after another member of the Flores family grew concerned in late July. A son told police he had not heard from Larissa since July 29, an unusual break in what he described as frequent communication. Family members tried calling Hector, Larissa and Matthew Flores Semyonov without getting answers. On Aug. 4, the concerned relative contacted Avondale police and requested a welfare check at the Litchfield Park home.
The relative met officers at the residence and allowed them to enter but stayed outside because, according to the police report, he feared what officers might find. No member of the household was located inside. Police later disclosed that the house contained a significant amount of blood and signs of an attempted cleanup. Investigators also tried to locate the missing family members through their cellphones, but the devices had been turned off and could not be located through the carrier.
The search soon moved to the yard. Investigators found two bodies buried behind the house, and police later confirmed the remains were Hector and Larissa Flores. Initial records from the Maricopa County Office of the Medical Examiner listed their causes and manners of death as pending. Officials have not publicly released a complete forensic account of the killings, and portions of the police material describing the first search of the residence have remained redacted.
Matthew Flores Semyonov was not found with his parents. Investigators instead concluded that he had left the country and identified him as a suspect. Avondale police requested help from the U.S. Marshals Service on Aug. 7. Federal agents obtained an arrest warrant for unlawful flight to avoid prosecution and began coordinating with law enforcement partners in other countries. The Marshals Service has not announced where it believes Flores Semyonov went, and no arrest has been publicly reported.
A police report subsequently provided a glimpse of family concerns before the disappearances. A relative said Flores Semyonov had learned Hector was having an affair and became upset that Larissa had not left her husband. The same relative recalled Flores Semyonov making threatening-sounding but nonspecific comments, including “you’ll get what’s coming to you.” Those accounts are part of the evidence gathered by investigators, but authorities have not publicly established the marital conflict as a definitive motive.
Family members also described Flores Semyonov as having changed after college. According to the police report, he moved back home, became more isolated and stopped drinking. The report referred to a mental health diagnosis but redacted its name. Another family account described him saying that plants told him they were thirsty while he watered them during the night. Such material has attracted attention in coverage of the case, but officials have not said a medical diagnosis caused the alleged killings, and the available evidence does not support making that conclusion independently.
That distinction remains important because Flores Semyonov has not appeared in court. The Marshals Service says Avondale authorities want him in connection with first-degree murder, dangerous domestic violence and abandonment or concealment of a dead body, while federal authorities want him for alleged flight to avoid prosecution. Those accusations have not yet been tested through a criminal proceeding, and investigators have not publicly released the full evidentiary case they would seek to present against him.
The victims’ family has largely stayed out of public discussion of those details. Through a representative, relatives said they were devastated, cooperating with police and grateful for support from friends, neighbors and the wider community. They asked for privacy while the investigation continued. The statement came as professional communities connected to Hector and Larissa separately mourned people they knew not as crime victims but as a professor, colleague, clinician and caregiver.
That contrast remains at the center of the case as of Sept. 22. Hector and Larissa Flores have been publicly identified and remembered through the institutions where they worked, but the man authorities accuse of causing their deaths remains outside police custody. Flores Semyonov is still listed as wanted by the U.S. Marshals Service, and officials have not publicly identified his current location. Until he is found, both the federal fugitive case and the unresolved questions surrounding his parents’ deaths remain open.
Author note: Last updated September 22, 2026.