A quiet welfare check at an Arizona home turned into an international fugitive investigation after police found human remains buried in the backyard. Authorities now believe 27-year-old Matthew Christopher Flores Semyonov may have fled the United States.
The case began after family members became concerned about Flores Semyonov and his parents. They asked police to check on the family at their Litchfield Park residence. According to the U.S. Marshals Service, officers found none of the three people inside the home.
Investigators soon found signs that something serious had happened inside. There was a “significant amount of blood” along with evidence that someone had tried to clean the residence. A later search of the property uncovered human remains buried in the backyard.
Fleeing the country after something like this won’t keep the law away for long
According to the police, the remains have not yet been formally identified. Authorities have not publicly named the victims. However, Flores Semyonov is suspected in the deaths of his parents.
The Avondale Police Department conducted the welfare check on Aug. 4 after concerns were raised about the couple and their adult son. Police initially classified all three as missing persons. The department also suspects evidence of foul play at the residence.
On Aug. 7, Avondale police formally requested help from the Arizona WANTED Violent Offender Task Force. The U.S. Marshals Service is now leading the search for Flores Semyonov.
Investigators believe the suspect left the country. The U.S. Marshals obtained a federal arrest warrant from the U.S. District Court for the District of Arizona. He is charged with unlawful flight to avoid prosecution. The case follows a similar manhunt for a murder suspect in New South Wales in a triple murder accusation.
U.S. Marshal Van Bayless said authorities will use domestic and international partnerships to find him and return him to Arizona. He stressed that crossing a border will not stop the investigation.
Flores Semyonov has not been charged with his parents’ deaths at this time. The Avondale Police Department remains responsible for the criminal investigation into their disappearance and suspected deaths.
The U.S. Marshals Service is coordinating with federal and international agencies to locate him. The Arizona WANTED Violent Offender Task Force includes 22 agencies and made more than 1,748 arrests in the last year.
Authorities warn that Flores Semyonov should be considered dangerous. The public is urged not to approach him or attempt to apprehend him.
Anyone with information can contact the U.S. Marshals at 1-877-WANTED-2 or email [email protected].
Published: Aug 13, 2026 07:30 am