How could a shooter get so close to the podium where Donald Trump was speaking? The Secret Service is facing criticism for "serious security breaches", but is pushing back against what the special unit calls false information.
It wasn't until the shots were fired that the 20-year-old shooter was discovered on the roof of a building just outside the cordoned-off area where Trump was holding his campaign rally.
An eyewitness tells BBC that he saw an armed man climbing up onto the roof – and that he tried to alert the police to the shooter.
Shortly afterwards, five shots were heard, according to the FBI. It took 22 seconds after the shots were fired for the armed security forces to reach the podium where Trump was standing.
The Secret Service, responsible for providing security, is now facing sharp criticism.
Multiple security breaches
Jim Cavanaugh, a retired special agent who previously worked with the Secret Service, says he is surprised that the shooter was able to get to a spot with a clear view of the podium where Trump was speaking.
There shouldn't be anyone on a roof. All elevated areas should be secured, he says to NBC.
Several security experts who have spoken to the TV channel call the assassination attempt on Trump the biggest security failure since Ronald Reagan was targeted in a similar assassination attempt outside a hotel in Washington in 1981.
Reports on Sunday claimed that the Secret Service had denied Trump's team's request for increased protection.
"This is completely false information. In fact, we added resources and expanded technology as part of increased campaign surveillance", the security service writes in a statement according to CNN.
The Secret Service has, however, launched an internal investigation into how the armed man was able to get close enough to harm the former president.
Tone down the rhetoric
An investigation is also pending in Washington, where Congress wants to see if mistakes were made. Several leaders from both parties have condemned the assassination attempt and are demanding answers about the security arrangements at the campaign rally.
We want to see if there's anything else that the American people need and deserve to know, says House Speaker Mike Johnson, a Republican, to NBC.
Until then, we must tone down the rhetoric. We need to bring down the high tone in our country, he says.
