Inches from death: An hour that shook America

The flinch was instinctive as the first crack sounded around Butler's showgrounds. Donald Trump's hand darted to his ear as more cracks came in. Screams welled up from the crowd as he ducked, and as Secret Service agents buried him in the mass of their bodies.

It had just gone 18:12 on Saturday, 13 July, and Thomas Matthew Crooks, having already been flagged by police as suspicious, had managed to climb onto a warehouse roof, line up his AR-15 style rifle, and fire a hail of bullets towards the former president.

What happened in just a few moments at Butler Farm Show grounds would shake American politics, and leave a nation asking how a man was able to enter the grounds with a powerful gun, climb to a firing spot unchallenged, and get within an inch of Trump's life.

Using witness accounts, original reporting and statements from law enforcement, the BBC has pieced together a picture of the events that chaotic day.

The late afternoon summer sun beat down from a clear blue sky, as this small town in Pennsylvania prepared for its biggest spectacle in years.

The crowds were flocking to a showground transformed into a slice of Americana; everything festooned in red, white and blue, a sea of flags, campaign posters covering almost every surface.

Greg Smith was among them. He had spent the day at his home in Butler with friends and family, eating BBQ and drinking beer, before heading down the road to take in the spectacle.

"We were hanging out, having a party. Then we were all like 'hey, Trump's here - let's walk up to the rally and look at him through the fence'," he told the BBC. "It was just a good time."

Corey Comperatore, 50, a retired volunteer firefighter and avowed Trump supporter, was also there with his wife and one of their two daughters. They scored a prime spot to the right of the stage, and waited for the show to begin.

Local police mingled with the crowd outside the event's security fences. Secret Service agents and state police worked together inside the perimeter, while anti-sniper teams were positioned on roofs of nearby buildings, watching.

Somewhere in that crowd was Crooks, a 20-year-old from nearby Bethel Park. But he wasn't with family, or friends, and his motivations were not the same. In the hours before, his parents Matthew and Mary had reported him missing to the police, saying they were "worried" that he had disappeared.

Security sources told CBS, the BBC's US news partner, that Crooks first came to the attention of police at 17:10, 52 minutes before Trump took to the stage, and was "identified as a person of interest". Why was that not disclosed?

It was 20 minutes later, at 17:30, that Crooks was noticed looking at a roof by a local SWAT team stationed in buildings outside the security perimeter.

One officer took a photo and radioed to others that he had seen a man peering through a rangefinder - a device hunters use to measure distance to a target.

They did not report seeing a gun. Crooks remained free to wander.

Another 22 minutes passed before Crooks was again spotted - at 17:52 - this time on the roof of a warehouse around 140m (400ft) from the stage. It was outside the security perimeter on a direct line of sight to the podium where Trump was due to speak.

Mr Smith was near that building, standing by a tree, and spotted Crooks too. "I looked over, and there's a guy crawling up the roof with a rifle," he told the BBC - the first time it appears anyone saw an actual weapon.

"We're telling police 'hey, there's a guy on the roof with a rifle', and they're running around on the ground like they don't know what's going on. It was, like, two minutes - this guy was crawling up the roof."

He said Secret Service agents on the roof of an adjacent building were "looking with binoculars" as he pointed.

Trump takes the stage at 18:02 wearing a dark blue suit, open-neck white shirt and red Make America Great Again baseball cap. He is shadowed by three Secret Service agents in dark suits, white shirts and dark sunglasses.

A full 10 minutes had elapsed since Crooks was spotted on the roof.

God Bless the USA (I'm Proud To Be An American) by Lee Greenwood blasts from festival loudspeakers hoisted high in the air.

Walking past several gold-trimmed flags, Trump shakes hands with supporters to applause and cheers. Within a minute he is at the podium, the crowd as his backdrop chanting "USA! USA!" and holding banners reading "Trump 2024" and "You're Fired".

"This is a big crowd, a big, big beautiful crowd," he tells the gathering in its thousands. "Hello Butler and hello to Pennsylvania, I'm thrilled to be back."

Around this time, approximately 140m away, Crooks is challenged by police.

According to Tom Knights, Butler's township manager, four of the town's traffic officers are radioed about a suspicious person on the roof. They "instinctively" bolt from their posts to confront the danger.

One of the officers is boosted by a colleague and pokes their head over the roof lip. They find themselves in the sights of an AR-15-style rifle held by a long-haired man with glasses. The officer is in an impossible position, and drops eight feet to the ground, according to Mr Knights.

The officers radio another alert, but Crooks remains unhindered.

Mr Smith later recalled continuing to point at the roof and yell to police. "I'm standing here like this," he told the BBC, "telling them 'hey there's a guy up here', and then I'm thinking in my mind like, 'why is Trump still talking? Why do I still hear him on stage?'"

But Trump is in full flow, launching into familiar topics about the country being "stolen", the "rigged" 2020 election, "crooked" Joe Biden and "laughing" Kamala Harris.

Seven minutes in, at 18:09, he turns the topic to immigration. "We have millions and millions of people in our country that shouldn't be here. Dangerous people. Criminals. Drug dealers," he says.

At about 18:11, he goes "off auto-cue" and turns to a chart on his right showing immigration levels, and rails at Mr Biden's border policies.

"And if you want to really see something that said... take a look what happened..."

He doesn't finish his thought. The time is 18:12, and Crooks fires his first shot.

A snap is heard and Trump flinches. More snaps, and Trump clutches his right ear and begins to duck beneath the podium.

A shout of "DOWN DOWN DOWN GET DOWN" is heard as confused screams well up from the crowd. Within seconds the former president is mobbed by four Secret Service agents as yet more shots echo around the grounds.

Shocked crowd members duck in their seats - there is nowhere to go. They know nothing of the condition of the former president now under a scrum of security.

To the left of the stage, a loudspeaker rig appears to have been hit by a bullet, gas escaping from the hydraulics as the speakers begin falling to the ground. Confused screams become ever louder.

A video posted to the TMZ website shows Crooks on the roof around this time, the air filled with the sounds of gunfire and the yells from people below. "What is he doing?" screams one woman, as a man warns "he's turning this way, guys".

But Crooks has only seconds to live. Secret Service counter-snipers acquire him as a target within 11 seconds of his first shot. Fifteen seconds after that he is dead, CBS quoted security sources as saying.

"I heard about four or five shots and everyone was running," said Mr Smith afterwards. "I stood by the tree and watched him get shot in the head by the Secret Service. They took him out but... security failure, 100%."

Back on the stage, Trump is buried under even more agents. "Hold, hold are you ready? On you," says one of the guards as his words are picked up by the podium microphone. "Move! Move!"

Officers in combat gear then take up positions around them, their assault rifles at the ready.

"Shooter's down, we're clear," an agent shouts and Trump is hoisted back into view. Blood covers his ear and there are spatters on his face and shirt collar, but he tells the agents, "let me get my speaker, let me get my shoes.... wait wait wait."

He then repeatedly punches his fist into the air and mouths the words "fight, fight, fight", before being hauled away by agents still using their bodies as cover.

Shouts of "USA! USA!" rise up as Trump is led off the stage, approximately one minute and 10 seconds after the first shot.

While the former president survived without serious injury, others had not. Some of Crooks' bullets missed Trump but struck the crowd. Mr Comperatore, the volunteer firefighter, was hit in the head as he shielded his family.

A doctor seated behind the stage, James Sweetland, tried to help. "Someone over there was screaming, 'He's been shot, he's been shot'," Dr Sweetland told the BBC.

"The guy had spun around [and was] jammed between the benches. There was a lot of blood."

He couldn't do anything to help. Mr Comperatore was dead.

Two other people, David Dutch, 57, and 74-year-old James Copenhaver, were critically injured, but survived.

A few hours later, back at home, Mr Smith recalled watching the "terrifying" aftermath on television. "There were a lot of kids up there with us, terrified. They're still terrified. My kid was terrified, crying and begging me to take him home.

"I can't accept that there is ever a reason for something like this to happen."

The would-be assassin was dead, Trump had survived, but a nation remains in shock, still starved for answers about how this could happen so easily.