Before he embarked on a cross-country journey, Cole Tomas Allen offered the people in his life a series of explanations for his absence, according to writings that the authorities say he left behind.
He had a personal emergency, he told his colleagues and the students he was tutoring. He told his parents simply that he had an interview.
But Mr. Allen appears to have had a much different and much darker plan when he set out on a train from California to Washington, according to two senior law enforcement officials who say he is now in custody, accused of charging through security outside the White House Correspondents’ dinner, setting off a flurry of gunfire.
Now, those who knew Mr. Allen are struggling to reconcile the man they knew with the shocking act of political violence that he has been accused of perpetrating.
The suspect, who the authorities have not publicly named but who was identified by the two officials as Mr. Allen, 31, of Torrance, Calif., is expected to be charged with multiple crimes in a court appearance on Monday.
The writing the authorities attributed to Mr. Allen bounced between remorse for the deception of friends and family and gratitude for a lifetime of love and support. In it, he displayed outrage at the policies put in place by the White House, and alluded to allegations of sexual misconduct, saying that he is “no longer willing” to allow a “traitor to coat my hands with his crimes” — an apparent reference to President Trump, though the writing does not mention him by name.
The two law enforcement officials who shared the writings with The New York Times asked not to be named because they had not been authorized to disclose the information.
It was uncertain on Sunday whether Mr. Allen had obtained legal counsel, and close relatives declined to discuss his arrest or did not respond to requests for comment.
The writing said the suspect had come to the Washington Hilton looking for members of the Trump administration.
“Administration officials (not including Mr. Patel): they are targets, prioritized from highest-ranking to lowest,” the writing reads, apparently referring to Kash Patel, the F.B.I. director. It was not clear from the writing why Mr. Patel was mentioned by name.
The language seemed foreign to Mr. Allen’s neighbors, former classmates and tutoring clients in Torrance, a suburb of Los Angeles. There, the home he shared was swarmed shortly before midnight Saturday by a S.W.A.T. team from the Federal Bureau of Investigation.
Mr. Allen was a registered “no party preference” voter — the California equivalent of an independent. His sole political contribution in available records appears to have been $25 to the campaign for Kamala Harris, the Democratic presidential nominee in the fall of 2024.
“He seemed like a completely average guy,” Max Harris, a senior at a local high school who had been tutored for several months by Mr. Allen, said late Saturday night as he stood near the crowd of federal authorities and onlookers who had gathered outside the modest, two-story house where Mr. Allen lived in Torrance.
“Like, I never would have expected anything like this from a guy like him.”
Mr. Allen was listed as a tutor with C2 Education, which issued a statement Sunday that said they were cooperating with law enforcement. “Violence of any kind is never the answer,” the organization said.
The authorities have said that the suspect in the Saturday attack was taken into custody shortly after charging through a security checkpoint and exchanging gunfire with federal law enforcement officials inside the Washington Hilton. He was armed with knives, a shotgun, and a handgun, authorities have said.
The suspect is initially expected to be charged with two counts of using a firearm and one count of assault on a federal officer using a dangerous weapon, Jeanine Pirro, the U.S. attorney for the District of Columbia, said on Saturday. He is scheduled to be arraigned on Monday in Federal District Court and additional charges are expected, she said.
Mr. Allen was born the oldest of four siblings in Los Angeles County.
As of Saturday night, Mr. Allen’s father was listed online as an elder at Grace Torrance, which describes itself as a Protestant church in the Reformed tradition.
In 2013, Mr. Allen enrolled at the California Institute of Technology, or Caltech, an elite research university in Pasadena, Calif. At that time, according to federal data, Caltech admitted less than 11 percent of its undergraduate applicants.
There, Mr. Allen studied mechanical engineering. He graduated with a 3.0 GPA, according to his LinkedIn profile.
In the summer of 2014, he did a summer internship at NASA’s Jet Propulsion Laboratory, according to his LinkedIn profile. And a local news clip from 2017 shows Mr. Allen, clad in a checkered collared shirt and sweater, demonstrating his design for a wheelchair emergency brake at a conference focused on designing products for older people.
He was also involved in the Nerf Club, in which members armed with foam toys organized campus battles, and belonged to a campus Christian fellowship. Another fellowship member recalled that while Mr. Allen was generally quiet and studious, he was not shy about defending his own interpretation of his faith.
“He was definitely a strong believer in evangelical Christianity at the time that I knew him,” the fellowship member, Elizabeth Terlinden, said.
After graduating from Caltech in 2017, Mr. Allen spent several years working as a mechanical engineer, a self-employed video game developer and a college test-prep tutor, according to his LinkedIn profile.
In 2022, he enrolled at California State University, Dominguez Hills, to pursue a master’s degree in computer science. The university said in a statement on Saturday that it had a record of a student matching Mr. Allen’s name earning a degree in 2025.
Bin Tang, a professor of computer science at the university, taught Mr. Allen in several classes.
“I am very shocked to see the news,” Dr. Tang said in an email. “He was a very good student indeed, always sitting in the first row of my class, paying attention, and frequently emailing me with coursework questions.”
Records shared by the two law enforcement officials show that Mr. Allen bought a handgun in October 2023 and a shotgun in August 2025.
According to the note shared by authorities, Mr. Allen told his colleagues and students in recent days that a personal emergency would keep him from his tutoring duties and told his parents that he had “an interview.”
Then he took a train from Los Angeles to Washington via Chicago, checking into the Hilton hotel a day or two before the hotel hosted the White House Correspondents Association dinner, Todd Blanche, the acting attorney general, told “Meet the Press” on Sunday.
Mr. Blanche added that initial evidence indicated that Mr. Allen had acted alone.
Alan Blinder, Devlin Barrett, Sonia A. Rao, Pooja Salhotra, Orlando Mayorquín, Laurel Rosenhall, Jin Yu Young, and Stephanie Saul contributed reporting. Georgia Gee contributed research.