Updated

A former FBI special agent gave an inside look into what federal investigators are looking for after they decrypted the killer's cellphone and laptop in hopes of discovering Thomas Crooks' motive.

Retired FBI Supervisory Special Agent Scott Duffey told Fox News Digital that, since the FBI announced that it successfully unlocked Crooks' electronics, they can now download the contents of his digital footprint.

"The FBI's cellular analysis surveillance team would be able to look through his phone, be able to download what is on there through software that they have and through cell tower information," he said.

"Since this is a rural area, did he leave that area? Was he venturing out or communicating with anybody?" Duffey asked. "They will be able to piece together his whereabouts."

US SECRET SERVICE DIRECTOR PLANS TO ‘STAY ON’ AS CALLS GROW FOR HER RESIGNATION

An undated image of Thomas Matthew Crooks.

An undated image of Thomas Matthew Crooks. (Handout via AFP)

Duffey said that the FBI's capabilities are "second to none" and that the agency will thoroughly search through Crooks' electronics.

"They're going to be looking for is who, if anyone, he was in contact with," he said. "And if not in contact with anyone, then gather information about what he was reviewing, reading and researching."

Agents of the Federal Bureau of Investigation walking through crime scene

The FBI decrypted Thomas Crooks' cellphone and laptop in hopes of discovering a motive. (Getty Images)

Duffey said the FBI will be investigating the extent of knowledge Crooks may have had about bomb-making.

The FBI previously said that 20-year-old Crooks had explosives inside his car, found parked near the Pennsylvania rally, and bomb-making materials at his home.

BREAKING INTO TRUMP SHOOTER'S CELLPHONE COMPLICATED BY MODERN TECHNOLOGY: EXPERT

"How far advanced was he in those devices? So were they improvised devices that were already ready to go, or was it materials that, for whatever reason, was just to throw dogs off and whatnot?" he questioned.

"And they [the FBI] will want to know how long he had been doing this," Duffey said. "The research that led into the ultimate act of taking a rifle up on top of a rooftop and then firing it into a crowd and ultimately towards the former President of the United States, Donald Trump."

FBI agents canvas Thomas Matthew Crooks’ neighborhood in Bethel Park, Pennsylvania

FBI agents canvas Thomas Matthew Crooks’ neighborhood in Bethel Park, Pennsylvania, on Monday, July 15, 2024. Investigators are speaking with neighbors about Crooks, who was killed on Saturday after attempting to assassinate former President Trump at a campaign rally in Butler, Pennsylvania. (Derek Shook for Fox News Digital )

Duffey said that federal agencies will also prioritize if Crooks left a final note before his attack at the former president's rally.

"Did he leave a manifesto? Did he write? Did he journal?" he continued. "Just amassing pieces of evidence."

The retired FBI agent said that if Crooks had not been killed by a Secret Service officer, the FBI would have interviewed him and deciphered his motive.

"The ultimate goal is to be able to get into his head, which is what the FBI would have done if he was taken into custody and interviewed – which we know that not to be true."

"Because of that, they have to go through troves of evidence and nothing better would be if he had been journaling, researching or reaching out to a best friend," he said.

Thomas Matthew Crooks

Bethel Park School District can confirm that the alleged shooter in the July 13, 2024, assassination attempt on former President Trump is a graduate of Bethel Park High School. Thomas Matthew Crooks graduated from Bethel Park High School with the Class of 2022. (Bethel Park School District)

Duffey said the "troves of evidence" will hopefully shed light on Crooks' political leanings or if he struggled with mental health.

FORMER SECRET SERVICE AGENT WARNS AGENCY ‘STRETCHED THIN’ WITH NEW RESPONSIBILITIES, LACK OF MANPOWER

"Was he anti-government? Was he seeing anybody for mental health diagnoses?" 

A view of a street sign in front of the home of 20-year-old Thomas Matthew Crooks

A view of a street sign in front of the home of 20-year-old Thomas Matthew Crooks, named by the FBI as the "subject involved" in the attempted assassination of former President Donald Trump, in Bethel Park, Pennsylvania, on July 15, 2024. (REUTERS/Aaron Josefczyk)

He said that the FBI will "spare nothing" to uncover Crooks' motive.

"I've often said in any type of crime, when somebody commits such a violent crime of such attention and, either by suicide or by an act of law enforcement, is no longer with us, that the FBI only has what is available to them through their devices and any friends, cohorts, or colleagues to at least give some idea, because the motive ultimately and always resides in the head of the doer," he said.

CLICK TO GET THE FOX NEWS APP  

"And, minus an interview, you are hoping that it's been at least put out, in some form of writing."