kidnap. the motive in this case remains unclear. david? >> all right, alex perez, thank you. next tonight, we are learning more about the victims and the survivors of that mass shooting at a food festival in california, you'll remember the pictures. the gunman unleashing at the family event. people running in panic. three people died. and what we've now learned about this case tonight. abc's will carr in gilroy, california, again this evening. >> reporter: tonight, investigators are scouring this massive crime scene, trying to figure out why santino william legan opened fire on a packed food festival. authorities now zeroing in on the murder weapon. they say the suspect legally bought the ak-47-style rifle in nevada on july 9th. the gun store posting on facebook the suspect "was acting happy and showed no reasons for concern." police say he then illegally transported the gun into california before killing three, including 13-year-old keyla salazar, who died as she stayed back with a relative with a cane.