Mary Bea Perez, a 9-year-old Hispanic girl, vanished from the Fiesta celebration with her family at Market Square in San Antonio, Texas, on April 18, 1999. Her disappearance in broad daylight prompted a large community search. A week later her body was found near Alazan Creek under an overpass at Interstate 35 and Laredo Street; she had been strangled.

The San Antonio Police Department investigated the killing without an immediate suspect and the family and community were left without answers for months. Later in 1999 a man named Tommy Lynn Sells was arrested in Del Rio, Texas, for other crimes; during that investigation he confessed to multiple killings in several states and admitted abducting, sexually assaulting, and killing Mary before dumping her body.