Image source, Getty Images

Donald Trump was speaking at the Butler Farm Show grounds on 13 July when the sound of shots rang out.

Screams broke out and Secret Service agents leapt on Trump to protect him. He was eventually led away, and it was soon revealed a bullet had grazed the side of his head.

Corey Comperatore, a former volunteer fire chief who was watching the rally from stands behind Trump, was shot and killed in the attack. Two others were wounded.

Secret Service counter-snipers identified Thomas Matthew Crooks, 20, perched on a nearby roof, as the suspect. He was shot and killed.

The agency came under intense scrutiny for the perceived security failures that allowed Crooks, armed with an AR-15 style rifle, to come so close to killing Trump. Secret Service Director Kimberly Cheatle resigned.

High-profile Republicans, including House Speaker Mike Johnson, pointed the finger at Democrats, saying some had fanned the flames of hate towards Trump.

Bernd Debusmann Jr
Reporting from the rally in Butler

Among Trump's supporters, there is a palpable sense of excitement that Trump has made it back here to Butler three months after narrowly escaping with his life."It's awesome," says Marann Moore, an Ohio resident who drove early this morning to get to the rally.

Moore - who says she's been a supporter of Trump since he first entered the national political stage in 2015 - says she's a fan of most of Trump's policies.

Her primary voting issue, however, is the border.

"I'm scared if people coming without being vetted," she tells me. "I think you should be able to come here. But legally, not illegally. Do all the paperwork and be vetted."

In the near three months since that assassination attempt in Butler, investigations by US Senators and the Secret Service have tried to uncover the security failings which allowed 20-year-old Thomas Crooks to shoot eight times at the former president.

In the below video, the BBC's analysis editor Ros Atkins examines key questions about what happened on that day:

Bernd Debusmann Jr
Reporting from the rally in Butler

Image source, EPA

One thing that immediately jumped out at me when I arrived here earlier is the heightened security presence compared to when I last came in July.

From where I'm standing just outside the venue, I can clearly see camouflaged snipers on every rooftop. They're peeking through binoculars and rangefinders at the massive crowd below.

Ahead of the event, we heard from the Secret Service and local authorities that many of the security issues that plagued the last event have been addressed.

Rather than having multiple command posts and lines of communications, for example, they now have a unified command post. All potential vantage points have also been covered with the help of Pennsylvania State Police and a variety of local departments.

Bernd Debusmann Jr
Reporting from the rally in Butler

I've been here since about 09:30 local time (14:30 BST) - well ahead of the rally's scheduled 17:00 start time. And safe to say, I'm not alone.

Already there are several thousand people arriving, causing a snarling traffic jam through the small town of Butler.

Throughout the massive parking area and on a pathway leading into the venue, vendors have set up to sell flags and T-shirts, many of them made for today's rally with words such as "celebrate the triumphant return" and "back to Butler 10/5".

Artists have set up here too. One man is painting a picture of Elon Musk - who's expected to make an appearance - and behind me a statue of Donald Trump has been erected with a plaque that says "tough as nails".

I'll be speaking to rally goers for much of today about what has brought them here, so stay tuned for that. Many have come from out of state and in the parking lot I see number plates from as far away as Kentucky and Florida.

Sam Hancock
Live page editor, in Washington DC

Image source, Evan Vucci/ AP

Donald Trump will today return not just to Pennsylvania, but to the exact same location where an attempt was made on his life in July - the Butler Farm Show grounds.

Last time it ended with an image (see above) of the Republican presidential nominee being escorted away by Secret Service agents, blood on his face and fist in the air.

In the hours that followed, it was revealed that the gunman, 20-year-old Thomas Crooker, had been shot dead and the Secret Service came under scrutiny. The agency’s chief, Kimberly Cheatle, later resigned - accepting “full responsibility for the security lapse”.

Since then, a second attempt has been made on Trump’s life, with 58-year-old suspect Ryan Routh pleading not guilty in a court this week.

We’ve got reporters on the ground in Butler, who’ll bring us the latest from the rally, and in North Carolina where Democratic presidential nominee Kamala Harris is returning later to survey Storm Helene damage. We back at base will bring you all that plus news lines and analysis, stay tuned.