WASHINGTON – He is a Caltech graduate once named teacher of the month. He made video games and developed a prototype for a wheelchair emergency brake.

Now, Cole Tomas Allen, 31, is the suspect in the shooting at the annual White House Correspondents’ Dinner on April 25, accused of embarking on a cross-country train trip and telling family members he was a "friendly federal assassin" out to target administration officials, according to authorities, including a senior law enforcement official.

“On to why I did any of this: I am a citizen of the United States of America. What my representatives do reflects on me. And I am no longer willing to permit a pedophile, rapist, and traitor to coat my hands with his crimes,” Allen wrote in a letter sent to family, published by the New York Post and confirmed by USA TODAY.

Allen, according to police, boarded a train from Los Angeles, checked into a Washington hotel that was the scene of the black-tie gala and fired a weapon outside the dinner attended by Trump and other top federal officials.

The attack threw into chaos one of Washington’s premier social events, which every year attracts some of the country’s most powerful people and the journalists who cover them. On the dais inside the massive ballroom, security agents quickly whisked Trump, first lady Melania Trump and Vice President JD Vance to safety as other guests in tuxedoes and evening gowns ducked under tables for cover.