What we know about the investigation into the attempted assassination of Trump

As investigations into the assassination attempt on former President Donald Trump intensified on Sunday, the US secret service also came under scrutiny. Questions are emerging about how the suspected gunman managed to fire a volley of shots from a rooftop overlooking the stage at the campaign rally in Pennsylvania where Trump was speaking.

The FBI identified the suspected shooter as 20-year-old Thomas Matthew Crooks of Bethel, Pennsylvania. He was armed with an AR-15 rifle and fired up to eight shots before a Secret Service sniper shot him, law enforcement officials told ABC News.

The suspect appeared to be wearing a T-shirt and light brown camouflage shorts that blended in with the colors of the building he was sitting on.

Watch the ABC News special “Trump Assassination Attempt Minute by Minute” Sunday at 8 p.m. ET.

The firearm seized at the scene of the attack had been legally purchased by the suspect’s father, according to an urgent search conducted by the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), according to multiple law enforcement sources.

Federal investigators said they found no links between the suspect and any international terrorist groups. Investigators said they were still looking into whether the suspect had ties to domestic terrorist groups.

According to the Pentagon, the suspect had no connection to the US military.

Officials said investigators are also combing the suspect’s social media channels for clues.

Investigators are looking into what sources say the suspected shooter consumed as misinformation and whether it played a role in the incident, law enforcement officials said. So far, investigators have not discovered any links to extremist organizations or individuals, although they continue to comb through information from the suspect’s phone and other digital devices, the sources said.

Trump posted on his Truth Social page that he suffered a gunshot wound to his right ear in the attack.

Trump had not even been speaking for 10 minutes and turned his head to look at a giant screen when the gunfire rang out, according to witnesses and a video of the moment. In the video, the former president can be seen grabbing his ear and falling to the ground as several gunshots are heard.

A man attending the rally was fatally shot and two other rally attendees were shot and wounded, federal officials said. Pennsylvania Gov. Josh Shapiro identified the deceased victim as Corey Comperatore. The other names were not immediately released.

Authorities found suspicious items in the shooter’s vehicle, which was parked outside the Trump rally, law enforcement sources told ABC News.

Bomb technicians and other experts have been called in to investigate, but there is no information yet on what the suspicious items were or whether they were potentially dangerous. Officials are awaiting information on what the items were and whether they contained explosives.

The FBI is leading the investigation. Investigators said they executed a search warrant for Crooks’ home overnight.

The roof from which the suspect fired the shot was examined during security preparations for the event, a law enforcement source told ABC News.

During these security measures, the roof was empty, the source said.

The investigation remains into why the Secret Service or local law enforcement did not station anyone at the building to prevent anyone from getting onto the roof.

Secret Service denies report that it rejected Trump team’s request for increased security measures

In a video, the former president, wearing a “Make America Great Again” hat, can be seen grabbing his right ear and falling to the ground as several Secret Service agents rushed to cover him with their bodies and people in the crowd also took cover.

Anthony Guglielmi, a Secret Service spokesman, released a statement on X on Sunday contradicting media reports that the Secret Service had rejected a request from the Trump campaign for additional security resources.

“There is a false claim that a member of the former President’s team requested additional security resources and was denied them. This is absolutely false. In fact, we provided additional protective resources, technology and capabilities as part of the increased pace of travel during the campaign,” Guglielmi wrote.

Some senators call for investigation of Secret Service

“I urge you to launch a full, public and comprehensive committee investigation into this assassination attempt and the failure to adequately protect the President,” Republican Senator Josh Hawley of Missouri said in a letter released Sunday formally asking the Senate Homeland Security Committee to investigate the attack on Trump.

The House Homeland Security Committee also called on Secret Service Director Kimberly Cheatle to testify soon.

ABC News’ Josh Margolin, Pierre Thomas, Luke Barr and Aaron Katersky contributed to this report.