Mariel Encarnacion was 9 when she vanished from her Arvin, California, home on September 11, 2011, along with her 7-year-old brother, Luis. The siblings were last seen at their residence around 10 p.m. The next day their mother, Mariela Mendizabal, was found brutally stabbed to death in the home.

Authorities believe the children were abducted by their father, Maico Encarnacion Lopez, who is the primary suspect in Mariela’s murder. Lopez reportedly had a history of instability and had recently separated from Mariela. He fled with the children and is believed to have possibly taken them to Mexico; a federal warrant was issued charging him with homicide and unlawful flight to avoid prosecution. He was reportedly seen with the children on public transportation in Los Angeles shortly after the disappearance, but there have been no confirmed sightings since.

The siblings’ whereabouts remain unknown and the case is unsolved. Anyone with information about Mariel, Luis, or Maico Encarnacion Lopez is asked to come forward.