An investigation is continuing into the assassination attempt on former President Donald Trump, who appeared at the Republican National Convention in Milwaukee Monday night — the first time he has been seen in public since he was shot and injured at his campaign rally in Pennsylvania.
The crowd at the convention cheered Trump, whose ear was bandaged after it was hit by a bullet on Saturday.
Details are emerging about the moments that led up to the shooting. Bystanders alerted law enforcement to the gunman on the roof of a building about 410 feet away from the stage at least two minutes before the first shot was fired at Trump, video analyzed by CBS News shows.
A local law enforcement officer with direct knowledge of the incident told CBS News three snipers — local tactical teams, deployed to assist the U.S. Secret Service — were stationed inside the building the shooter used in his attack. The operations plan had them stationed inside the building looking out windows toward the rally.
One of the local snipers inside spotted the gunman, Thomas Matthew Crooks, outside and looking up at the roof, observing the building and disappearing, according to the officer. Crooks came back, sat down and looked at his phone. At that point, one of the snipers took a picture of him. Crooks took out a rangefinder and the sniper radioed to the command post. Crooks disappeared again and then came back a third time with a backpack. The snipers called in with information that he had a backpack and said he was walking toward the back of the building.
Officers believe that Crooks might have used an air conditioning unit to get on top of the roof. By the time other officers came for backup, he had climbed on top of the building and was positioned above and behind the snipers inside the building, the officer said.
Two other officers who heard the sniper's call tried to get onto the roof. State police started rushing to the scene, but by that time, a Secret Service sniper stationed in a building behind the former president had already killed Crooks, firing off one round, according to multiple law enforcement officials.
The FBI is investigating whether the shooter was a politically motivated homegrown domestic violent extremist, and investigators are still combing through his background. Justice Department officials told reporters that investigators have the shooter's phone and were examining it at the FBI lab in Quantico, Virginia.
Shooter bought a ladder before Trump rally
Two law enforcement sources told CBS News the shooter purchased a ladder at Home Depot prior to the shooting, but it is unclear if he brought the ladder to the rally venue on Saturday. This was first reported by CNN.
Home Depot said in a statement, "we condemn the violence against former President Trump, and our thoughts are with him, the other victims of Saturday's horrific events, and their families."
— CBS News' Nicole Scanga and Adam Yamaguchi
Neighbors of Trump rally shooter react to investigation
Authorities have searched the home of the man who tried to assassinate former President Donald Trump – putting a small town in Pennsylvania in the spotlight of the investigation.
One anonymous neighbor told CBS News Pittsburgh that he had to disconnect his phone after receiving 100 calls from around the world related to the shooting, which killed a rally attendee and injured Trump and two others.
A person was seen walking a suitcase into the shooter's home on Monday night. The person did not respond to media questions, and could not be immediately identified, CBS News Pittsburgh reported.
Some neighbors recalled interactions with the gunman and his family.
"I had a really pleasant conversation with them," said Alleghany County councilman Dan Grzybek, who lives on the same street as the shooter and visited the home while campaigning. "I got the perception they were nice people."
Grzybek said he fears the shooter's actions will "result in further political violence."
"I think people are worried that conspiracy theorists are going to come to the area and do something not particularly smart," he said.
Cellphone video shows security failures
Cellphone video taken Saturday shows rally attendees pointing toward the shooter and trying to alert authorities to his presence — a full two minutes before the 20-year-old fired at Trump.
Less than 15 seconds before the shots, people are seen running away from the area. Moments later, some in the crowd begin shouting that the man on the roof has a gun.
The gunman killed Corey Comperatore, a firefighter. He also wounded two others aside from Trump: 57-year-old Marine Corps veteran David Dutch and 74-year-old James Copenhaver.
Seconds later, a Secret Service counter sniper fatally shot Crooks.
— CBS News' Charlie De Mar and Kelsie Hoffman
FBI conducts nearly 100 interviews
The FBI said it had conducted nearly 100 interviews of law enforcement officials, attendees at the rally and other witnesses as of Monday afternoon, as it investigates the attack as a potential act of domestic terrorism.
It has also received hundreds of digital media tips, according to a press release, but has not identified a clear ideological motive.
The FBI believes the shooter — who was not previously known to the FBI — acted alone, with a gun that was purchased by his father.
Searches of the shooter's home and vehicle are complete, according to the FBI, and authorities are analyzing his electronic devices.
Shooting followed "absolute and abysmal failure," expert says
A former police chief who worked event security for two former presidents said the shooting followed an "an absolute and abysmal failure" on the part of the Secret Service to protect Trump. The agency is ultimately responsible for the candidate's safety, said Stan Kephart.
"You don't get to blame other people," said Kephart, who is now a consulting expert on law enforcement event security. "They are under your control."
At least a dozen police officers and sheriff's deputies were assisting the U.S. Secret Service and Pennsylvania State Police with rally security.
Biden says he shouldn't have said "bullseye" when referring to Trump
President Biden said in an interview with NBC News' Lester Holt that he should not have used the word "bullseye" when referring to how his campaign should treat Trump, but still wants to put the focus squarely on his opponent's record and rhetoric heading into November.
"I was talking about focus on, look, the truth of the matter was, what I guess I was talking about at the time was, there was very little focus on Trump's agenda," Mr. Biden said Monday.
"It was a mistake to use the word," the president said, but added, "I meant focus on him. Focus on what he's doing."
"I'm not the guy that said, I want to be a dictator on day one. I'm not the guy that refused to accept the outcome of the election. I'm not the guy who said they won't accept the outcome of this election automatically," Mr. Biden said. "You can't only love your country when you win. And so, the focus was on what he's saying and the idea."
Asked if he had done any "soul searching" about his rhetoric, Mr. Biden said, "How do you talk about the threat to democracy, which is real, when a president says things like he says? Do you just not say anything, because it may incite somebody?"
"I've not engaged in that rhetoric," Mr. Biden insisted. "Now, my opponent is engaged in that rhetoric. He talks about, there'll be a bloodbath if he loses. Talking about how he's going to forgive all the ... I guess suspend the sentence of all those who were arrested and sentenced to go to jail because of what happened in the Capitol."
Sniper who took out gunman fired one round
The Secret Service sniper who neutralized the gunman fired one round and was assisted by a spotter, according to two federal law enforcement officials with knowledge of the response to the shooting.
The sniper who took out the gunman was located on the roof behind and to Trump's to his left — the square furthest to the right in the below map.
FBI continues looking into Trump shooter's background
The man who attempted to assassinate Trump purchased 50 rounds of ammunition from a gun store in Bethel Park, Pennsylvania, before arriving at the rally site, according to a law enforcement bulletin from the Department of Homeland Security and the FBI obtained by CBS News.
The FBI is investigating whether the shooter "was motivated by a violent extremist ideology or had any association with additional plotters or co-conspirators."
Investigators found three suspected improvised explosive devices after the shooting, including two in the shooter's vehicle parked near the rally site, the bulletin reads.
Both agencies advised law enforcement about the potential for retaliatory acts of violence following Saturday's shooting given the online threats of violence after the attempt on Trump's life.
"Some individuals' reactions to politically and socially divisive topics have prompted violence ... and some individuals - including some (Domestic Violent Extremists) - potentially will view political and social tensions as an opportunity to use or promote violence to further their ideological goals," the bulletin reads.
Source: Bomb-making material found in shooter's home, vehicle
A law enforcement source confirmed that authorities found rudimentary bomb-making material at the gunman's residence and in his vehicle. The FBI is analyzing the devices at Quantico.
Trump says assassination attempt had "impact"
The attempted assassination on former President Donald Trump had "an impact," he told ABC News on Monday.
Trump was asked by ABC News' Jonathan Karl if the attempt on his life had changed him.
"I don't like to think about that, but, yes, I think has an impact," he said, adding that he hoped the bandage on his ear would be removed by the time he speaks on Thursday to the Republican National Convention.