The perpetrator of the attack on Trump was spotted and photographed on the roof by law enforcement nearly 30 minutes before firing

Thomas Matthew Crooks, the perpetrator of the assassination attempt against Donald Trump, was suspiciously spotted on the roof by law enforcement almost 30 minutes before shooting at the former president's rally in Butler, Pennsylvania.

According to the local WPXI, Crooks was spotted at least twice by members of the Beaver County emergency services unit team approximately 26 minutes before he fired shots at the former president and the crowd at the Pennsylvania rally.

Crooks managed to wound former President Trump, who suffered a bullet graze to the ear, and two other people. A former fire chief, Corey Comperatore, was also killed in the bloody attack.

According to sources quoted by the WPXI network, police officers detected the presence of a "suspicious" man on the roof, took a picture of him and reported him at around 17:45. Subsequently, after the fateful attack, it was determined that the man in the photo was Crooks. At the time he was photographed, officers were unable to determine whether or not he had a rifle.

However, about 26 minutes after being photographed, Crooks opened fire from the rooftop of the building that had a clear view of the stage where Trump was speaking. Seconds after wounding the former president and killing a member of the audience, he was shot down by a Secret Service sniper.

The news that Crooks was spotted by authorities nearly 30 minutes before firing comes after a viral video on social media showed that several witnesses warned law enforcement that there was a man on the roof ready to open fire at any moment.

The video, cited by national media outlets such as The Washington Post, was posted Sunday night and shows several witnesses shouting and directing at least one police officer toward the roof from where Crooks fired at Trump.

In the video, one man hurriedly shouts "Officer! Officer!" as others point toward the building. "He's on the roof!" another woman points out. In the video, a police officer can be seen looking toward the top of the building.

According to the Washington Post, the video revealed on Sunday supports the statements of witnesses who spoke to the media moments after the assassination attempt and who reported that they tried to warn authorities of the impending attack.

The media outlet relates that the video shows "a chaotic scene in which bystanders started calling out to police nearly a minute and a half before the shots rang out."

With these two reports, the pressure on the Secret Service continues and since the attack has been questioned for what experts consider a serious security lapse.