In the days after the attempted assassination of former President Donald Trump, investigators have looked into the suspected shooter's history, finding evidence that suggests he was isolated from the community and bullied in school, multiple sources briefed on the investigation told ABC News. While they continue to search for a motive for the attack, investigators are wondering whether the shooter had expected to survive the attack.
The suspect's former classmates have described him as quiet and said he came across as lonely, without many friends. Investigators are also looking into what appeared to be disinformation that the suspect was consuming before the attack and whether it played any role in it, according to law enforcement sources.
Investigators have not found any evidence that the suspect -- 20-year-old Thomas Matthew Crooks -- worked with anyone else to plan the attack and they have not found anything atypical in an investigation of this sort. He also does not appear to have any ties to extremist groups or individuals, law enforcement sources told ABC News.
The suspect had two phones, one on him and a second one found at his home, multiple law enforcement sources confirmed to ABC News. One of the phones, which was unlocked by the FBI, did not turned up any significant information about the suspect's motives -- only what sources described as "routine" information for a 20-year-old male.
Investigators also found a tactical vest in the suspect's car, though it is unclear why he did not wear it during his fatal assault on the former president's rally -- leaving some investigators wondering whether he anticipated dying in the attack. The shooter also asked his employer if he could take a day off on Saturday -- the day of the attempted assassination -- but said he would return to work perhaps as soon as Sunday, the day after this attack, according to law enforcement sources.
The firearm recovered at the scene of the Trump assassination attempt was legally purchased by the suspect's father in 2013, an urgent trace conducted by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) found, according to multiple law enforcement sources.
According to evidence gathered by investigators, the suspect recently purchased ammunition both online and in-person.
Before the shooting, the suspect would occasionally go target shooting and use his father's AR-15 style rifle -- and on the day of the shooting, the shooter told his father that he wanted to go to the range, so his dad let him have the gun, a source familiar with the matter told ABC News. Since this wasn't an unusual occurrence, the father didn't think anything of it at the time, the source said.
The shooter had previously sought to join his high school rifle club but was rejected and asked not to return, two students who were members of the team at the time, told ABC News.
The suspect attended what was described as "preseason" for the rifle club -- which was held before tryouts -- but he did not make it to the tryouts stage, the two team members said. Both students said Crooks was a "bad shot."
"He didn't just not make the team, he was asked not to come back because how bad of a shot he was, it was considered dangerous," said Jameson Myers to ABC News.
The suspect was employed as a dietary aide at the Bethel Park Skilled Nursing and Rehabilitation Center at the time of the shooting. According to investigators, the shooter does not have any known history of mental illness.
Investigators found a remote transmitter in the suspect’s pocket that may have been intended to set off two suspicious devices found in the suspect’s car and one in his home, law enforcement sources told ABC News.
Devices at both locations were similarly constructed in ammunition containers using components including receivers that appear to have been paired with the remote control found in the suspect’s pocket, sources said.
According to one expert, no evidence as of now suggests the shooter expected to survive the attack. He exhibited some behaviors and issues similar to that of mass shooters -- he was a loner, bullied, angry with some conditions in his life and bought a large amount of ammunition -- John Cohen, a former acting undersecretary for intelligence and ABC News contributor, told ABC News in an interview.
"Whether they are committing suicide by cop or they understand that their death will provide them the notoriety that they require, in most cases, individuals who exhibit the behavioral characteristics this shooter is exhibiting go into the attack not expecting to survive," Cohen, who has been studying mass shooters for almost a decade, told ABC News.
"Some behavioral characteristics that have come to light already is that this is an individual who clearly suffered challenges in developing and maintaining interpersonal relationships. He was identified as a loner, he appeared to be disconnected from other parts of the community, [and had] a fascination with guns," Cohen said.
According to what evidence has surfaced so far, the suspect appears to have exhibited characteristics consistent with those of mass shooters, suggesting the shooter may have seen this as an opportunity to end his life, Cohen said. Whether he expected to survive or not, will not change how investigators look into the attack, Cohen said.
"What officials are going to be looking for in the investigation are going to be first motive, and they're going to want to determine whether this was an ideologically motivated attack or was it an attack that was motivated by some sense of personal grievance or dispute?" Cohen said.
"I suspect based on what we've learned thus far, we're going to find that there were multiple factors that led this individual to conduct this attack," Cohen said.