The gunman who killed his three daughters, a chaperone who was supervising his visit with the children and himself in a Sacramento County church was known to have struggled with mental health issues, officials said. New details also reveal that David Mora Rojas, 39, also used a "ghost gun" in the shooting. Mora Rojas also overstayed his visa after entering California from his native Mexico on Dec. 17, 2018, on a non-immigrant visitor visa, U.S. Immigration and Customs Enforcement spokeswoman Alethea Smock told The Associated Press.