The suspect left behind significant clues, including a satchel, two 9mm guns, and high-capacity magazines that matched the ballistics from both crime scenes. However, his motive remains elusive as investigators delve into his history to bridge the gaps in his known background.

Authorities have indicated that the suspect aimed to inflict harm, specifically targeting the Ivy League institution and its distinguished professor, Nuno Loureiro.

CNN law enforcement analyst and former Secret Service agent Jonathan Wackrow highlighted evidence of premeditation, such as the acquisition of firearms and a bulletproof vest.

The suspect took calculated measures to evade detection. He switched the license plates on a rental car tied to the shootings, masked his identity, and managed to bypass Brown University’s extensive network of 1,200 security cameras by choosing a building with limited surveillance and multiple access points for his attack.

The biggest challenge, Wackrow noted, is uncovering the suspect’s motive, especially since there is no opportunity for interrogation or prosecution. Even thorough searches of digital footprints and physical evidence might not provide answers.

While investigators have traced some of the suspect’s movements in the years leading up to the attacks, much of his history remains shrouded in mystery.

Investigators have mapped some of the suspect’s movements in the years before his attacks, but much of his past remains a mystery.

He was enrolled in Brown from September 2000 to April 2001, when he took a leave of absence before formally withdrawing in July 2003, the university said.

There has been no formal explanation from the university on the basis for the leave, but according to CNN’s chief law enforcement and intelligence analyst John Miller, it could also point to a potential motive.

Miller said investigators will likely ask questions like: Did he blame a life event for derailing his success as a former student who was described by his then-classmates as “brilliant” but also exceptionally difficult? What issue caused him not to return?

Details on the suspect’s whereabouts between 2001 and 2017, however, have proved elusive at this stage.

But the suspect’s strategies do suggest he may have been planning for an encounter with police or an escape, Wackrow said.

And it begs the question, according to Miller: What happened to make the suspect change course and decide to take his own life? One scenario, he says, could be the suspect was alerted authorities were on his trail.

What were his movements after the shootings?

The suspect’s last known address was in Miami this year, and he rented a storage unit in Salem starting from an unspecified date in November.

He rented a hotel room in Boston from November 26 to 30 before renting a grey Nissan Sentra with Florida plates in the same city and then driving in the car to Brown University on December 1.

The car was seen several times by witnesses in the area of the school over the course of the next 12 days.

On December 13, the suspect opened fire at students in the on-campus auditorium of the Barus and Holley building, killing Ella Cook and MukhammadAziz Umurzokov, and injuring nine others.

Over the next day, the suspect returned to Massachusetts and switched the licence plates of the rental car during his time there to an unregistered plate from Maine.

On December 15, the suspect fatally shot Loureiro at the professor’s home in Brookline before immediately driving back to a storage facility in Salem where he had rented a unit.

It appears the suspect then swiped into his storage unit in Salem the same day and did not swipe out, Rhode Island Attorney General Peter Neronha told CNN.

Details of the autopsy released Friday estimated the suspect died on December 16, two days earlier than officials previously believed.

The development called into question a line in the affidavit filed by prosecutors, which said Neves Valente called the car rental agency at the airport in Hartford, Connecticut on Thursday.

A federal agent testified a man identifying himself by the name of the suspect called into the branch and asked to return the rented Nissan Sentra there.

Some leads developed in the investigation turned out not to be valid, according to Neronha, which he said is not unusual. When asked by CNN’s Erin Burnett whether the Thursday call wasn’t actually from the suspect, Neronha said, “That’s correct.”

Beyond the discrepancy, authorities on Thursday spent frantic hours trying to track the suspect and the car they believed he was driving, and had information he would be returning his rented car in Boston and boarding a flight out of Logan International Airport, according to a law enforcement official.

His storage unit served as a “logical base of operations,” said Miller, and his arrival in the Brown University area nearly two weeks before the shooting indicates he had been planning for the attack.

Was there any relationship between the suspect and the MIT professor he killed?

Investigators were only able to identify a potential link between the Brown University shooting and the MIT professor killing in the past two days after officials initially said there was no connection between the crimes.

After authorities confirmed the suspect and Loureiro were students at the same university, it left more uncertainty as there’s no information the two had any relationship beyond briefly overlapping as physics students and a shared time on campus.

Still, authorities say he targeted the professor.

Nuno Morais, one of his former classmates, told the Portuguese website Publico the suspect and Loureiro were among the top students at the school, but their personalities were starkly different.

A former colleague of Loureiro said the professor and the suspect were enrolled in the best physics course in Portugal and described their academic environment as highly competitive.

“It’s completely inexplicable,” Bruno Soares Goncalves, president of the Institute of Plasmas and Nuclear Fusion at Instituto Superior Tecnico in Lisbon, told CNN.

Some of the questions investigators will be asking, according to Miller, are: Did Loureiro and the suspect know each other? Were they competitors or rivals? Did the suspect see Loureiro as an enemy he felt he needed to kill or someone he blamed for any failures?

The suspect had to research the home address of Loureiro, and it was a highly targeted killing, which points to premeditation, Miller said.

A former classmate of the suspect told CNN’s Burnett he recognised Loureiro when the news of his death came out. Scott Watson, a professor at Syracuse University, said the MIT professor would sometimes come to Brown, but added he was unsure if Loureiro and the suspect were friends.

Who was the tipster who helped crack the case open?

At Thursday’s news conference when officials announced the suspect was found dead, they repeatedly praised an unidentified tipster and graduate of Brown University who broke the case open, saying “everybody in Providence owes this individual a debt of gratitude.”

The author of the post is the same individual seen in the photo released by Providence Police as they sought to talk to the man they believed to have been “in proximity” to the suspect, according to Providence Mayor Brett Smiley.

Police later interviewed him, and he told them he recognised the person seen in surveillance images released by police as the man he saw near the car shortly before the shooting.

The Reddit poster, identified in the affidavit only as John, said he first encountered the man inside a bathroom in the Barus and Holley building and noticed his clothing seemed inadequate for the cold weather.

Once the man left the building, John saw him approach the Nissan and appear to unlock it with a key fob before suddenly turning from the vehicle and walking in a different direction, the affidavit said.

John said he remained outside as the man kept circling back to the area before quickly changing directions every time he saw John, the document said.

At one point, John confronted the man, asking him why he kept circling the block, he told investigators, according to the affidavit, to which the suspect responded: “Why are you harassing me.”

John then kept walking down the street as the man walked toward the car and the two didn’t have any further encounters, the affidavit said.

The rental car was just one piece of data investigators used to link the Brown shooting suspect to the fatal shooting of the MIT professor, along with a financial probe, the storage unit and extensive security footage.