Shocked and fearful Maine residents kept to their homes for a second night as hundreds of heavily armed police and FBI agents searched intensely for Robert Card, an Army reservist authorities say fatally shot 18 people at a bowling alley and a bar in the worst mass killing in state history.

Much of Thursday’s search focused on a property belonging to one of Card’s relatives in rural Bowdoin, where trucks and vans full of armed agents from the FBI and other agencies eventually surrounded a home. Card and anyone else inside were repeatedly ordered to surrender.

“You need to come outside now with nothing in your hands. Your hands in the air,” police said through a loudspeaker. In most instances when police execute warrants — even for suspects wanted for violent crimes — they move quickly to enter the home.

But hours later, after repeated announcements and a search, authorities moved off and it was still unclear whether Card had ever been at the location, state police said.