Dramatic new body cam video shows cops clambering on to roof before stand off with Trump's attempted assassin

Dramatic new bodycam footage captured the moment Pennsylvania cops scrambled into action after shots were fired at Donald Trump. 

Footage from the July 13 event showed the moment a police officer confronted shooter Thomas Crooks after spotting him on a nearby roof, with the cop leaving the roof moments before shots were fired. 

The bodycam footage showed the officer peeking up onto the roof for only a second before spotting the gunman, at which point he sprinted to the ground and radioed to other law enforcement that Crooks was strapped with a 'long gun.' 

It comes amid mounting scrutiny on the response of local police and Secret Service agents at the scene to the shooting.  

The footage, which is just over four minutes long, began with the officer being raised onto the roof where Crooks had stationed himself, around 150 yards from where Trump was speaking from. 

Although Crooks is not seen directly in the footage, the cop, who has not been named, later claimed that the shooter pointed his AR-15 style at him. 

The officer immediately began sprinting across a grassy area and towards Trump's rally. 

Officials released the footage without any sound for the beginning of the episode, however the timestamp on the video shows the cop duck behind a vehicle at 6:11pm - the same time Trump was shot at. 

While crouched behind a car door, the officer assembled his own rifle, before shouting to other officers that the gunman 'was this close, and he turned around on me.' 

As other officers raced to try and find Crooks, the officer gestured to the rooftop and said he was 'straight up.' 

'Right where you picked me up bro, he was on that left side.' 

Crooks was shot dead within a matter of seconds after shots rang out by Secret Service snipers on another nearby perch. 

By the time the officer moved back to the building, heavily armed teams in camouflage had convened on the area. 

The unnamed cop barked a description at them as they readied to breach the building, saying Crooks was 'laying down... he's got glasses, long hair.' 

The footage ends with the officer briefly informing the teams what happened minutes prior, saying: 'I climbed the wall, and I poked my head right in front of him bro... he's got a book bag, he's got mad s***.'