It was a sweltering Pennsylvania afternoon, hot enough to keep the medics busy as people wilted in the blazing sun. But the heat had hardly tempered the enthusiasm of tens of thousands of people on the Butler Farm Show grounds who were waiting for Donald J. Trump.

When he finally showed up, the crowd, saturated in Trump gear, shouted in collective excitement when he hit his usual marks. They booed when he mentioned President Joe Biden, jeered when he spoke of a rigged election and roared when he said he would make America great again.

Then there was a new sound. Pop.

A firecracker, it seemed. Trump grabbed at his ear. And then: Pop. Pop. Pop.

Suddenly, a day of big emotions — glee, unity and righteous anger — was now shattered by fear. Around the grandstand where Trump had been speaking, beneath an enormous American flag suspended between two cranes, the spectators crouched. Secret Service officers swarmed over Trump.

It was now clear what was happening. Thousands of people, from those in the bleachers to the many watching from a large grassy field, dropped to the ground almost in unison.

Just before the shots rang out, some in the crowd said, it seemed as if law enforcement snipers who were perched atop a barn had noticed movement nearby. The snipers seemed to be focusing on something off to the side of the grandstand in the direction of a building and a water tower just outside the farm show grounds.

Supporters of Trump took cover as shots were fired. One spectator was killed, and two were critically injured, officials said.

“I saw them with their binoculars,” said Craig Cyrus, 54, who had come over from New Castle, Pennsylvania. “Then they got their guns.”

Once the shooting broke out, he said, the snipers returned fire.

“The first thing I thought to myself was, ‘America’s under attack’,” said Corey Check, a local conservative activist and Republican committeeman. “I grabbed the hands of a couple of people I didn’t even know. We said the Lord’s Prayer.”

Some began to cry and others screamed, while law enforcement officers shouted for everyone to get down. One of the audio speakers, apparently hit by a gunshot, toppled over.

When the popping ceased just a few seconds later, and heads rose again, the grim aftermath came into view.

Sid Miller, the commissioner of the Texas department of agriculture, who had come to the rally to cheer on Trump, said he turned and saw a person behind him bleeding profusely, their white clothes reddening as people gathered around to help. Others saw a man directly behind Trump, who appeared to be bleeding from the head. Several at the rally said they would later see a couple of people being carried out, limp and covered in blood.

In the moment, all eyes quickly turned to Trump. Some, in the few seconds that felt like an infinity, were fearing the worst.

“I couldn’t stop crying,” said Eduardo Vargas, 31, who was sitting not far behind Trump. “I thought I just saw the President get killed in front of my face.”

But Trump returned to his feet. He had a little blood on his forehead. But he seemed not to have been badly injured. He raised his fist in the air.

The crowd cheered “USA! USA!” though the cheers were not quite as robust as they had been just a few minutes earlier.

New York Times News Service