Trump gunman seen as threat before attack, was lost in crowd

Donald Trump's would-be assassin was flagged as "suspicious" up to an hour before he began shooting and his phone's history showed he'd searched for images of the Republican, senators have heard amid growing calls for the head of the US Secret Service to resign.

In two closed briefings to lawmakers in the House and Senate on Wednesday, law enforcement officials, including the Secret Service, shared limited new information about security and the man who opened fire at a Trump rally in Pennsylvania on Saturday.

Wyoming Senator John Barrasso said the Secret Service told them they had spotted the attacker one hour before the attack, but then lost sight of him in the crowd.

“He was identified as a character of suspicion because [he had] a rangefinder as well as a backpack. And this was over an hour before the shooting actually occurred,” he told Fox News.

“So, you would think over the course of that hour, you shouldn't lose sight of the individual."

It was also revealed during the briefings that the gunman had visited the site of the attack, the Butler County fairgrounds, in the days before the assassination attempt and had previously searched on his phone for symptoms of a depressive disorder, an official familiar with the briefing told CBS News, the BBC's news partner.

The attacker had also used his phone to search for images of both Trump and President Joe Biden. FBI Director Wray told lawmakers on the call that more than 200 interviews had already been conducted and 14,000 images reviewed.

Multiple Republican senators criticised the lack of transparency from investigators on their call and expressed outrage that Trump was allowed to take the stage even after a threat was identified.

"I am appalled to learn that the Secret Service knew about a threat prior to President Trump walking on stage," tweeted Senator Marsha Blackburn of Tennessee.

A law enforcement official involved in the investigation told CBS that a sniper from a local tactical team deployed to assist the Secret Service took a picture of the gunman looking through the rangefinder, and immediately radioed to a command post to report the sighting.

According to ABC News and other US outlets, the 20-year-old gunman was spotted again on the roof of a building 20 minutes before the attack began, officials revealed.

He was killed by Secret Service snipers within 26 seconds of opening fire on Trump.

Multiple senators who participated in the call complained that investigators did not answer their questions and demanded the resignation of Secret Service Director Kimberly Cheatle.

"The egregious security failures and lack of transparency around the assassination attempt on President Trump demand an immediate change of leadership at the Secret Service," tweeted Utah Senator Mike Lee.

Wisconsin Senator Ron Johnson called the briefing to lawmakers "unbelievably uninformative" and said investigators only took four questions from lawmakers.

Other senior Republicans also called for Ms Cheatle to resign. Senate Minority Leader Mitch McConnell said after the call that "the nation deserves answers and accountability" and a change in leadership at Secret Service would be "an important step in that direction".

House lawmakers similarly were briefed on Wednesday by law enforcement about security and what led up to the Saturday shooting.

Republican Speaker of the House Mike Johnson also called for Ms Cheatle to quit. He said he plans to open an investigation in the House.

"It'll be comprised of Republicans and Democrats to get down to the bottom of this quickly, so the American people can get the answers that they deserve," he told Fox News.

FBI Director Chris Wray, who participated in the calls, told lawmakers that no motive has yet been identified for the gunman.

Ms Cheatle, a 27-year veteran of the Secret Service, is due to testify next week to the Republican-controlled House Oversight Committee and House Homeland Security Committee.

The attack is being investigated by the Department of Homeland Security's inspector general, and President Biden said he would direct an independent review be opened.