Thomas Crooks researched Ethan Crumbley, watched livestream of Trump just before trying to kill him

Failed assassin Thomas Matthew Crooks researched school shooter Ethan Crumbley and other mass shooters – and took a screenshot from a livestream of former President Trump speaking just moments before opening fire, it emerged Friday.

The troubling search history leads investigators to believe that loner Crooks, 20, was mostly focused on a mass-casualty event — and that Trump’s rally close to his home in Pennsylvania was more about convenience than an ideological target, a US official briefed on the issue told CNN .

His research included looking up how to build explosives, the report said — with some found in his home, and a detonator also lying next to his body after he was finally killed by a sniper.

Crooks also looked up mass shooters, law enforcement sources told The Post — including Crumbley, who was just 15 when he gunned down four classmates at Oxford High School in December 2021.

Crooks had a photo on his phone of the mass shooter just after his arrest — and also had information about Crumbley’s parents, who are both convicted of involuntary manslaughter for failing to stop their son’s carnage, the CNN report said.

Trump shooter Thomas Matthew Crooks’ last online search was for porn

As well as researching Trump’s movements, Crooks had looked up President Biden and the schedule for the Democratic National Convention, suggesting his motive was not specific ideology but instead a headline-grabbing massacre.

The gunman then scoped out the Trump rally in Butler, Pa. — somehow being allowed to climb on a roof and almost assassinate the former president despite long raising suspicion — while also monitoring a livestream, taking a screenshot moments before opening fire, CNN said.

One of Crooks’ two phones had over a dozens contacts, as well as lots of images of high-profile elected officials, sources told The Post.

On the day of the rally, Crooks’ online searches included photos of the rally location, and for a local gun store where he later purchased ammunition.

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That Saturday morning, Crooks visited the farm grounds for over an hour.

He then returned home, where investigators believe that he grabbed an AR-15 rifle owned by his father.

Crooks’ dad, Matthew Crooks, later told authorities that he saw his son leave with the rifle, and assumed he was going to the shooting range they frequently visited together, CNN noted.

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So far, investigators have refrained from offering a specific motive for the shooting, which only hit Trump’s ear thanks to a sudden head movement while killing one innocent attendee and critically wounding two others.

Family and people who worked with Crooks have described him as quiet without any overt political affiliations.

A pair of former high school classmates remembered him being cut from the school rifle team for being a bad shot.

In April, Crooks searched online for information on major depressive disorder and depressive crisis treatment.

Authorities later found explosive devices in Crooks’ car, as well as a bullet-proof vest, additional magazines, and a drone, officials who briefed lawmakers on Wednesday said.

At the Crooks’ family home in Bethel Park, investigators also found 14 firearms and more explosives, as well as a second cell phone, a laptop and a hard drive.

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