Moises and his brother Justin resided in Irvine, California at the time they went missing. Their parents, Helen Romero and Moises Romero Sr., separated in 2004, while Moises Sr. was in jail for driving while intoxicated. According to Helen, Moises Sr., was abusive and served jail sentences for domestic violence.

Helen allowed Moises, Justin and their four sisters to visit Moises Sr. in San Francisco, California late in 2004, after the separation. Several days after the children arrived, Moises Sr. called his wife and asked if he could send Moises, Justin and their five-year-old sister to Mexico to visit their grandparents, Arnulfo and Maria Romero, for two weeks. Helen trusted the older Romeros and the family had visited them annually for the past several years, so she consented. Six days later, Moises and Justin's sister called her mother from Arnulfo and Maria's home and said she was homesick. Helen insisted they send the girl home, but allowed the boys to stay because they were enjoying themselves. A week later, on January 16, 2005, Moises Sr. was killed in a drunk driving accident in California.

Moises and Justin never returned from their visit to their grandparents. Arnulfo and Maria moved out of their Jalisco home without leaving a forwarding address, and took their grandsons with them. Helen has gone to Mexico twice to try and recover them, but they keep changing residences. Helen believes Arnulfo and Maria are probably being assisted by their other sons; one is a doctor employed at a Morelia, Michiocan hospital and the other is an attorney in Zamora, Michiocan.

Photographs and vital statistics for Arnulfo and Maria are unavailable. The children's current whereabouts are unknown and their cases remain unsolved. Both Moises and Justin were born in California and are American citizens.