(CNN) The gunman who opened fire at the Gilroy Garlic Festival in California, had a shotgun, a clown mask and wilderness survival items in his car, according to a newly-released search warrant.

Authorities say 19-year-old Santino William Legan opened fire at the food festival on July 28, killing three people, including a 6-year-old boy and a 13-year-old girl. More than a dozen people were wounded.

Investigators searching Legan's silver Honda Accord found more than 50 items in the car, per the warrant, which was released Thursday.

Among the items found: a Remington 870 tactical shotgun, ear plugs, a gas can, a wilderness training manual, binoculars, a plastic ammunition cans and a Smith & Wesson rifle bag. A pamphlet for the Gilroy Garlic Festival was also found, as were four license plates -- two from California and two from Nevada, where the vehicle was registered.

Legan was shot multiple times by three responding police officers before killing himself with a self-inflicted gunshot wound to the head, Gilroy Police Chief Scot Smithee has said.

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