In a Nation Armed to the Teeth, These Tiny Missteps Led to Tragedy

At the same time, Republican states including Florida and Texas passed new laws allowing people to carry guns openly, or carry concealed weapons without a permit.

More than 30 states also have “stand your ground” laws. Some have recently strengthened their “castle doctrine” laws, making it more difficult to prosecute homeowners who claim self-defense in a shooting.

“People become paranoid and over-worried — and then comes an unannounced knock on their door,” said Mr. Lowy, founder of Global Action on Gun Violence, a gun-control group based in Washington.

Byron Castillo, 51, knows what it’s like to be the one making that unannounced knock.

On the morning of Jan. 30, 2020, Mr. Castillo said he was sent to a second-floor apartment in High Point, N.C., to repair and repaint damage from a leaking kitchen. He announced himself as the maintenance man and knocked three times. The tenant inside responded by opening the door and shooting Mr. Castillo in the stomach without a word of warning, he said.

He dragged himself to his truck and drove to the apartment complex office, where he collapsed on the floor to wait for an ambulance. He spent one month in the hospital and another five months recovering on his couch, trying to rebuild strength in his legs and cope with the pain in his chest, where surgeons had cut him open.

Mr. Castillo said he later learned that the repair job had been in a first-floor apartment.

The High Point Police Department said prosecutors declined to bring charges. In a 2020 statement reported by local news outlets, the police said that “through unfortunate circumstances, Mr. Castillo attempted to gain entry mistakenly into the wrong apartment,” and that the man who shot him thought he was a burglar.

Mr. Castillo still cannot believe it.

“I was with my brushes and rollers in my hand,” he said. “How would it be a threat for you? To kill you with a brush?”