The internet poster called President Trump a “sociopathic mob boss,” said the administration “lies like it breathes” and accused Democratic leadership of engaging in “‘bipartisanship’ with Nazis.”

Federal authorities are looking into whether the man at the keyboard who used the name “coldforce” may have been Cole Tomas Allen, who was charged Monday with trying to assassinate President Trump, according to people familiar with the investigation who spoke on condition of anonymity.

They are seeking to understand better what may have motivated Mr. Allen, 31, whom they have accused of coming to Washington with a pump-action shotgun, a handgun and three knives to attack the White House Correspondents’ dinner.

A review of the user’s archived posts on Bluesky, a social media platform popular among left-leaning users, shows that the account often wrote or promoted posts that took liberal positions on political issues.

Most posts, which begin in late 2024, do not advocate violence and are unremarkable on the liberal forum. The user posted most frequently about the war in Ukraine, expressing frustration with the Trump administration for “betraying” allies. Recently, the account was also writing or sharing posts about what the writer called a “dumbass” war in Iran and the administration’s aggressive immigration enforcement.

But some posts suggested a sense that the American system was no longer working.

In May 2025, the user accused the three branches of government of engaging in “treasonous behavior” and called it a “civic virtue issue, basically a moral issue, and that’s not fixable with laws.”

Earlier this year, the user hinted at something more ominous.

“I’m getting the impression that a lot of American politicians and staffers think this is all a game,” the person wrote in January. “Not really looking forward to the ‘this is not a game’ portion of history that is 99 percent likely to be coming up.”

In the Bluesky posts, “coldforce” frequently refers to Mr. Trump as a “traitor.” In several posts, the user alludes to allegations of sexual misconduct on the part of the president.

Some of the language echoes a roughly 1,000-word note that federal authorities say was written by Mr. Allen. While that note does not name President Trump, it lays out targeted administration figures “prioritized from highest-ranking to lowest.”

The writings were signed: Cole “coldForce” “Friendly Federal Assassin” Allen.

There were other signs that give investigators reason to explore links between the Bluesky account and Mr. Allen. The user self-identifies as a Protestant and refers to working as a teacher. The user also identifies as a “random Californian guy” and refers to experience attending “two different, secular, California-based universities.”

Mr. Allen is from Torrance, Calif., a suburb southwest of Los Angeles. He attended the California Institute of Technology and California State University, Dominguez Hills, was active in a campus Christian fellowship and had been tutoring at a test-prep company in recent years.

In a statement on Monday, Bluesky said that the “coldforce” account was taken down for violating company policies, which prohibit “posts that amplify misinformation, or glorify violence or harm.”

The posts are still viewable through online archives.

Many posts circulated by the user came from people who are seen as more moderate figures. They include Will Stancil, a lawyer and activist also known for his online political punditry, and Bill Kristol, a conservative writer and fervent Trump opponent.

Sprinkled throughout the user’s posts are references to the “Retief” series, a popular satirical science fiction saga, and “The Lord of the Rings.” The user’s avatar is a character from “Gintama,” a Japanese manga comic series.

Mr. Allen was a registered independent voter in California. His only 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.

A post last month by “coldforce” suggests a growing frustration.

“More important question is ‘when do the (between 0 and 5, inclusive) adults in America realize that this is not tenable and sitting around waiting for someone else to do something about it is not working,’” the user wrote. “Can’t think of the last time i saw anyone on/offline take responsibility for fixing the problem.”

Devlin Barrett and Chelsia Rose Marcius contributed reporting.