The motive of the Gilroy Garlic Festival gunman remains unknown, but the FBI announced Tuesday it is opening a domestic terrorism investigation into the shooting that left three dead and 13 injured; the shooter also killed himself as police closed in. The 19-year-old gunman did not leave behind a manifesto, but there were signs he was "exploring violent ideologies," according to FBI special agent-in-charge John Bennett, who described his ideology as "fractured" and said it's not clear "what, if any, ideology he settled on." The FBI also says it has discovered a "target list" the shooter compiled, which included religious institutions, courthouses, federal buildings, and other sites, the AP reports. Political groups from both parties were also included on the list, CNN reports.
Also to be investigated: whether the gunman communicated with anyone "regarding these ideologies," and whether he discussed his plan with anyone in advance of the July 28 festival, Bennett said, per the San Jose Mercury News. "Much of our work remains ongoing," he said. "One piece of evidence does not necessarily constitute a motive. Hence the need for thorough, methodical investigation." The following weekend's El Paso shooting, which left 22 dead, is also being investigated as domestic terrorism as well as a hate crime, CBS News reports. (It's not yet clear whether the next day's Dayton shooting, which left nine dead, will be investigated as either, but the gunman appears to have been a self-described "leftist.")