Omar Vargas was three years old when he vanished on April 22, 1995, during a family trip to an Evangelical church gathering in Agua Prieta, Sonora, just across the border from Douglas, Arizona. He was about 3 feet 6 inches tall, 35 pounds, with black hair, brown eyes, a brown oblong birthmark above his navel, and a habit of sucking the two middle fingers of his right hand. On the day he disappeared he wore a dark blue western-style shirt, dark jeans and black western boots.

Witnesses said Omar had been playing outside the church with other children and was seen leaving with the group but failed to return; one missing-child profile states an unidentified adult male led him away. The case turned into a cross-border investigation involving local authorities in Arizona and Agua Prieta, search-and-rescue teams, tracking dogs, a helicopter and FBI assistance.

His mother later died in a traffic accident in Mexico in 1997 while searching for him.