The shooter who opened fire at a Donald Trump rally on Saturday told his boss he needed that day off because he had “something to do,” according to multiple law enforcement officials.
Thomas Matthew Crooks told his coworkers he would be back to work on Sunday.
By 3 p.m. on Saturday, Thomas Matthew Crooks was at the security screening area for the Trump rally in Butler County, Pennsylvania. He first aroused suspicion when he passed through the magnetometers carrying a?rangefinder, which looks similar to a small pair of binoculars and is used by hunters and target shooters to measure distances when setting up a long-range shot, according to a senior law enforcement official briefed on the investigation.
The rangefinder would not have prevented Crooks from getting through the security screening point, but it did attract the attention of security personnel who kept an eye on him until he left the secure area.
Gene J. Puskar/AP, Facebook, CNN
Investigators are unsure of where Crooks went after he left the screening area but the working theory is that he went to his car to retrieve the rifle.
Around the same time witnesses alerted police that Crooks was crawling on the roof, one of the four counter-sniper teams observed Crooks looking at their position through the rangefinder, according to the senior law enforcement official.
“They were looking at him while he was looking at them,” the official said.
Crooks gained access to that rooftop by climbing on top of the building’s air conditioning system and hoisting himself up, according to a senior federal law enforcement official briefed on the investigation.
After the shooting, multiple law enforcement sources said investigators found a bulletproof vest, three fully-loaded magazines and two remote-controlled explosive devices in Crooks’ car. Investigators are uncertain as to whether Crooks had a plan to use the body armor, nearly 100 rounds of additional ammunition from those loaded magazines, and two remote-controlled bombs, had he escaped after the shooting.
Additionally, after a search of his residence, investigators discovered another bulletproof vest, another remote-controlled explosive device and a 3D printer, according to multiple law enforcement sources.