Multiple investigations are being conducted into the attempted assassination of former US president Donald Trump at a campaign event in Butler, Pennsylvania.
New details have emerged since Saturday's shooting, which left Trump, 78, lightly wounded, along with a number of questions, chief among them the motive of the 20-year-old gunman, Thomas Matthew Crooks.
Here's the latest on the investigation:
In the aftermath of the attack, one of the main questions being asked is how the gunman was able to secure a perch on the roof of a nearby building with a clear sightline of the stage where Trump was speaking.
Secret Service Director Kimberly Cheatle has said the building was outside the agency's security perimeter and securing it was the responsibility of the local police.
Lawmakers were briefed by the FBI and Secret Service in a closed session on Wednesday and were provided with a timeline of notable events on the day.
Crooks "was identified as being suspicious one hour before the shooting," said Republican Senator John Barrasso of Wyoming. "The Secret Service lost sight of him."
Rallygoers spotted Crooks on the roof of the building a few minutes before Trump took the stage and alerted police on the ground to his presence.
Crooks opened fire with an AR-style rifle just minutes after Trump began to speak, leaving him with a bloodied ear.
Crooks was shot dead by a Secret Service sniper 26 seconds after firing the first of eight shots.
The revelations provoked outrage among some Republicans including House Speaker Mike Johnson, who has called for Cheatle's resignation.
Representative Jim Jordan, chairman of the House Judiciary Committee, asked FBI Director Christopher Wray in a letter whether "communications breakdowns" had hampered the ability of law enforcement to "identify the shooter as a potential threat and mitigate the threat before he took action?"
Jordan also claimed that "whistleblowers" had told the committee that the Secret Service had "limited resources" because of the just-concluded NATO summit in Washington and an upcoming visit to Pennsylvania by First Lady Jill Biden.
Investigators have determined that Crooks, who lived in a town about 50 miles (80 kilometers) from Butler, acted alone and have not been able to identify any strong ideological or political leanings.
He lived with his parents, worked in a retirement home and recently graduated from community college.
A search was conducted of his electronic devices -- a laptop and two cellphones -- according to lawmakers briefed by the FBI.
Among his recent internet searches were queries about Trump, President Joe Biden, the dates of the Butler rally and the upcoming Democratic convention.
Other searches were for FBI Director Wray, Attorney General Merrick Garland and a member of the British royal family.
"They did get into the phone finally, good news," Frank Figliuzzi, a retired FBI assistant director, told MSNBC.
"Bad news, it's not helping them at all with regard to motive," Figliuzzi said. "There's still no motive and I caution people -- don't expect some kind of logical motive here, don't apply logic to lunacy."
"I remind people of the Las Vegas mass shooting years ago (in which 58 people died)," he said. "We still don't have a motive for that."
Speaking to Fox News, Robin Dreeke, a former FBI agent, also said establishing a motive for Crooks may prove elusive. "I think this was more of something he was going to try to do to get notoriety," Dreeke said.
Trump, in a post on Truth Social, said he was "shot with a bullet that pierced the upper part of my right ear."
The former president appeared at the Republican National Convention in Milwaukee on Monday with a white bandage on his injured ear.
Two rally attendees were seriously wounded in the shooting and a 50-year-old firefighter, Corey Comperatore of Freeport, Pennsylvania, was shot dead.
Crooks, the gunman, was slain by a Secret Service sniper stationed on the roof of a building overlooking the stage where Trump had been speaking.
