Gunman in Trump assassination attempt researched Oxford High School mass shooter Ethan Crumbley before attack

(WWJ) Thomas Crooks, the young man who tried to assassinate former President Donald Trump, looked up Michigan school shooter Ethan Crumbley about a week before last Saturday's deadly attack .

That's according to reports by CNN and the New York Post , who said those details were shared by the FBI and U.S. Secret Service in a Wednesday briefing with lawmakers and others familiar with the investigation into the shooting at a Trump campaign rally in in Butler, Pa.

While Crooks' motive is still known, the would-be assassin’s recent trail online is giving investigators hints as to his possible mindset before the attack. FBI behavioral experts are building a profile of Crooks based on the findings, the FBI told lawmakers, per CNN .

On his primary cellphone, the FBI said it found an image of the mugshot of Ethan Crumbley, who shot and killed four classmates, wounding seven others at his Oakland County high school in 2021. Investigators also found Crooks had looked up information about both Crumbley and his parents, the FBI said.

James and Jennifer Crumbley made headlines when they were both found guilty of involuntary manslaughter , becoming the first time parents of a school shooter have been prosecuted in connection with their child's crimes.

Ethan Crumbley, who surrendered to police at the scene at Oxford High School, was convicted in four charges of first degree murder, as well as terrorism and other charges. He is serving a life=without-parole prison sentence.

As for signs that Crooks was planning an attack, the FBI says Crooks' online trail shows Crooks he'd followed Trump's movement, but also President Biden's and the schedule for the Democratic National Convention. This could suggest, according to the FBI, that Crooks' motive was not specific ideology but instead a headline-grabbing massacre.

Also on Crooks' phone, the FBI said it found that the 20-year-old had searched websites for information on major depressive disorder and depressive crisis treatment — but they didn't find a manifesto, journal or such other clues that it's typical for a shooter to leave behind.

FBI officials said the AR-style rifle used in the attack was legally purchased by Crooks' father. After the shooting, authorities found explosive devices in Crooks’ car , along with extra magazines, a bulletproof vest and a drone, officials who briefed lawmakers on Wednesday said.

Corey Comperatore, a 50-year-old retired firefighter who was attending the Trump rally with his family was fatally shot. Three other people were injured, including Trump, who has said he was shot in the ear.