The FBI says it has opened a domestic terrorism investigation into the mass shooting at the Gilroy Garlic Festival and has discovered the shooter had a list of potential targets.

John Bennett, FBI special agent in charge in San Francisco, said in a press conference on Tuesday that while investigators have not made a determination about 19-year-old Santino Legan's motive in the shooting, which left four people dead including Legan, "we have uncovered evidence throughout the course of our investigation that the shooter was exploring violent ideologies," with these ideologies being "varying" and "competing."

Bennett also said investigators discovered the shooter had a list of organizations that "may have been potential targets of violence," including religious institutions and political organizations from both major parties, although there were no specific individuals named on this "target list."

"It's a fractured interest in targets," he said. "There was nothing that was all one side or the other."

Also included on this list were federal buildings, courthouses, and the Gilroy Garlic Festival, Bennett said.

Now, a "full domestic terrorism investigation" has been opened, Bennett said, noting that this requires the suspect to have committed an act of violence "in furtherance of their political or social goals." Bennett had previously said it had "not been determined" whether Legan had been motivated by white nationalism, ABC News reports. Asked on Tuesday whether white nationalism was one of the ideologies the shooter may have been motivated by, Bennett said the FBI is "still exploring" this but "cannot rule it out."

Brendan Morrow