Watch Part 1 of the special report: The Plot to Kill Trump: What we know and what comes next

(NewsNation) — Former President Donald Trump returned to Butler, Pennsylvania, three months after surviving an assassination attempt.

“Exactly 12 weeks ago, this evening, on this very ground, a cold-blooded assassin aimed to silence me,” Trump told the crowd at the Butler fairgrounds, where he was joined for the first time at a rally by Elon Musk.

Security was noticeably heightened for Trump’s return visit, with snipers positioned around the perimeter and increased local, state and federal law enforcement presence.

A Senate investigation has revealed significant security failures leading up to the attempt. The Secret Service, which recently saw its director step down, acknowledged it failed to properly secure the perimeter and couldn’t even determine who was in charge of various security assignments.

This special report, “The Plot to Kill Trump: Back to Butler,” explores the investigation, law enforcement failures and what went wrong.

You can watch the full report in the player above.

Trump returns to Butler, Penn., with Musk in tow

Musk joined Trump at his rally Saturday in Butler, the Pennsylvania city where the Republican presidential nominee survived an assassination attempt earlier this year.

He took the stage on Saturday to praise the GOP presidential nominee and slam Democrats he claimed “want to take away your right to vote, effectively.”

“The true test of someone’s character is how they behave under fire. We had one president who couldn’t climb a flight of stairs and another who was fist pumping after getting shot,” Musk said, swiping at President Biden.

Before Trump’s entrance, his running mate, Ohio Sen. JD Vance, referred to the attempted assassination, joining in on the Democratic blame game.

“Even after that terrible assassination attempt that took one man’s life and nearly took many others, they continue to use dangerous, inflammatory rhetoric,” Vance said. “The media has continued to call Donald Trump, the guy who actually won his primary, a threat to Democracy.”

Trump began his rally with a moment of silence for the firefighter who was killed during the attack. Speaking at the same location, Trump said time stopped on July 13 and called the shooter an “evil villain.”

Supporters: Butler rally was ‘exciting,’ not ‘scary’

Rallygoers Heather Hertig and Shelly Nadler attended both former President Donald Trump’s Butler, Pennsylvania, rallies. Rather than be scared upon return to the small city where shots rang out, the pair told NewsNation’s Brian Entin that Saturday’s event felt like “camaraderie.”

“You feel like a part of it. Now, instead of just coming to see Trump talk, it’s more of an emotional, like you’re a part of things … It’s not just an election. It’s about togetherness,” Hertig told NewsNation.

“I felt like I needed to have some closure, because it was just so surreal when we were here the last time, and it was so traumatic,” Nadler added.

Why don’t we know more about Thomas Crooks? 

Twelve weeks after the first attempt on Trump’s life at a Pennsylvania rally, little is known about his shooter’s motive and background.

Local authorities spotted the accused shooter, Thomas Matthew Crooks, 20, multiple times before he opened fire, including with a range finder at 5:38 p.m. Despite alerts to command, effective action wasn’t taken before Crooks fired from the roof of a nearby building at 6:12 p.m.

“This was a failure on the part of the United States Secret Service,” said Ronald Rowe, the agency’s acting director. “It’s important that we hold ourselves accountable.”

Three months after the shooting, investigators have released little information about Crooks or his motives. While they know he planned the attack through internet searches and practice at a gun range, no manifesto or explanation has emerged.

NewsNation’s Sean Noone, Anna Kutz, Damita Menezes and The Hill contributed to this report.