On June 24, 1993, Medellín carried out a gang initiation at T.C. Jester Park in Houston, Texas, along with five others: Peter Cantu, Ramon Sandoval, Efrain Perez, Raul Villareal and Derrick O'Brien.
Two girls who had attended a birthday party, 14-year-old Jennifer Ertman and 16-year-old Elizabeth Peña, took a shortcut through the park to get home before an 11:30 p.m. curfew.