Witness claims Trump's security were warned about gunman on the roof minutes before open fire

A witness claims he warned security about a shooter on the roof just minutes before former US President Donald Trump was shot.

Yesterday (July 13) at around 6:15pm, multiple gunshots rang out while Trump, 78, addressed the crowd at an outdoor rally in Butler, an hour outside Pittsburgh.

Following the incident, Trump said he’d been struck by a bullet in the ‘upper part of [his] right ear’ and that he’d been taken to hospital after ‘much bleeding took place’.

Following his discharge from hospital, officials have confirmed that one rally spectator had died, while two others in attendance were critically injured.

All three of the victims were male, according to the FBI.

The suspected shooter has since been identified as 20-year-old Thomas Matthew Crooks from Bethel Park in Pennsylvania.

According to witness Greg Smith, he saw someone 'bear-crawling' up the roof and that he 'had a rifle'.

"I'm thinking to myself 'Why is Trump still speaking, why have they not pulled him off the stage'... the next thing you know, five shots ring out,” Smith recounted to the BBC.

"We noticed the guy bear-crawling up the roof of the building beside us, 50ft away," he continued. "He had a rifle, we could clearly see a rifle.

Greg Smith claimed he'd alerted police to a shooter at the rally (BBC)

"We're pointing at him, the police are down there running around on the ground, we're like 'Hey man, there's a guy on the roof with a rifle'... and the police did not know what was going on."

Smith claims that he tried to alert authorities about Crooks for ‘three to four minutes’ and questioned why the Secret Service wasn’t positioned around the perimeter of the rally.

"Why is there not Secret Service on all of these roofs here?" he said. "This is not a big place. "[It's a] security failure, 100% security failure."

He said he later saw the agents shoot the gunman: "They crawled up on the roof, they had their guns pointed at him, made sure he was dead. He was dead, and that was it - it was over.”

In a statement published Sunday (July 14) morning, an FBI spokesperson wrote: “The FBI has identified Thomas Matthew Crooks, 20, of Bethel Park, Pennsylvania, as the subject involved in the assassination attempt of former President Donald Trump on July 13, in Butler, Pennsylvania.

“This remains an active and ongoing investigation.”

An AR-style rifle was later recovered from the scene, but a motive for the shooting is yet to be confirmed, authorities said.

The bullet grazed Donald Trump's ear. (Trump Campaign Office / Handout/Anadolu via Getty Images)

Earlier today, a Secret Service spokesman confirmed in a follow-up statement that agents had ‘neutralised the shooter’ and ‘quickly responded with protective measures’.

They added that Trump is ‘safe and being evaluated’.

When asked if law enforcement knew that the gunman was on the roof before he started shooting, Kevin Rojek, Special Agent in Charge of the FBI’s Pittsburgh Field Office replied 'that is our assessment at this time'.

Following the incident, Pennsylvania State Police Lt. Col. George Bivens released a statement regarding the shooter's position outside the rally perimeter.

“It is incredibly difficult to have a venue open to the public and to secure that against any possible threat against a very determined attacker,” Bivens told reporters.

“That’s a huge lift to try to do.”