Trump shooting updates: Shooter flew drone near site hours before shooting

The roof where the suspected gunman fired shots at former President Donald Trump had been surveyed during security preparations for the event, a law enforcement source told ABC News.

The roof was empty during those security preparations, the source said.

As reports of suspicious activity came in, a search was initiated, the source said. It was unclear how the suspect climbed onto the roof to quickly get off shots before a Secret Service counter-sniper located and killed him, the source said.

Officials continue on Sunday to investigate whether the dead suspect was connected to domestic extremists, the source said. The early investigation turned up no ties to international terrorism, the source said.

-ABC News' Pierre Thomas and Luke Barr

Sen. Josh Hawley, R-Mo., formalized his calls for the Senate Homeland Security Committee to investigate the attack on Trump in a letter to committee Chairman Gary Peters Sunday morning.

"I call on you to launch a full, public, and comprehensive committee investigation into this assassination attempt and failures to adequately protect the president," Hawley wrote.

Because Republicans are in the minority in the Senate, Peters, D-Mich., is required to call a hearing for it to proceed.

Former Vice President Mike Pence issued an updated statement Sunday morning condemning political violence.

"Karen and I thank God that President Trump is safe and recovering following yesterday's attempted assassination and are grateful for the swift response by Secret Service that undoubtedly saved lives. We are praying for his full recovery and for those lost and injured in this horrific attack. There is no place in America for political violence and it must be universally condemned," he wrote in a post on X.

-ABC News Kelsey Walsh

House Speaker Mike Johnson on Sunday called on Americans to "turn the rhetoric down" following the assassination attempt on former President Donald Trump.

"This is a horrific act of political violence. It ought to be roundly condemned. Obviously, we can't go on like this as a society," Johnson said on NBC News' "Today."

"We've got to turn the rhetoric down. We've got to turn the temperature down in this country. And we need leaders of all parties on both sides to call that out."

-ABC News' Justin Ryan Gomez