There’s no clear way to stop shooters like the one that killed a TSA agent at Los Angeles International Airport on Friday, House Homeland Security Committee Chairman Michael McCaul said Sunday morning.

The Texas Republican told Candy Crowley on CNN’s “State of the Union” that authorities in Los Angeles missed Paul Anthony Ciancia, the suspect in the airport shooting, by a “matter of minutes.” Ciancia’s relatives in New Jersey had warned officials that the 23 year-old exhibited signs of mental illness and suicidal tendencies in emails. But law enforcement officers arrived at Ciancia’s residence about 45 minutes after he had left to attack the airport Friday morning, McCaul said.