The people in charge of security at the Gilroy (CA) Garlic Festival relied on the industry’s best practices, employing tall fences and metal detectors and coordinating among several law enforcement agencies.

Officers responded to Sunday’s assault within a minute and neutralized the shooter despite being outgunned.

And yet they couldn’t prevent a tragedy – three deaths and at least 12 people injured.

The attack illustrates the difficult of protecting an outdoor event in a large venue, USA Today reports.

Police in the Northern California town of Gilroy, about 80 miles southeast of San Francisco, said the gunman cut through a back fence to gun down visitors at the popular festival’s final day.