The staff members of The Wall Street Journal sent a letter to newsroom leaders on Monday accusing the paper’s former editor-in-chief, Gerard Baker, who has been an editor at large at The Journal since leaving the top job in 2018, of violating rules that apply to those who work on the news side.

The letter, from the board of the Independent Association of Publishers’ Employees, the union that represents Journal staff members, criticized a column by Baker on race and accused him of tweeting in a way that went against the paper’s social media policy.

While Baker expresses opinions in a weekly column, called Editor at Large, The Journal had classified him as a member of the news division, just as it had during his five-and-a-half-year run as the editor-in-chief.

On Tuesday, The Journal reassigned Baker, formally making him a member of the opinion staff, which is led by the editorial page editor, Paul A. Gigot, and is run separately from the news department. Those who work on the opinion side do not have to abide by the rules that apply to the paper’s news reporters and editors. They have more leeway in The Journal’s pages and on social media.

The Journal said the move had been in the works before the IAPE union sent the letter. “Conversations about Gerry’s move to Opinion have been underway for some time,” a spokeswoman said. in an emailed statement. “His new, expanded role will include podcasts and other projects.” Baker did not immediately reply to a request for comment.

The IAPE’s letter was addressed to Matt Murray, Baker’s successor as editor in chief, and Almar Latour, who last month was named publisher of The Journal and the chief executive of its parent company, Dow Jones, which is part of Rupert Murdoch’s media empire.

The letter singled out a May 15 column by Baker headlined “The Often Distorted Reality of Hate Crime in America.” He led it with a description of the murder of Ahmaud Arbery, a black man who was shot while jogging in Georgia after he was pursued by white men, a killing that was captured on video.

The IAPE criticised the column, saying it “posits the highly controversial argument that black people commit more hate crimes than white people” and adding that to “prove” that he uses only his own single weighted statistical calculation, with no attribution or context from experts either to support the idea or provide contrary views.” The letter also flagged several posts from Baker’s Twitter account that, it said, violated the paper’s social media policy.

The British-born, Oxford-educated Baker led The Journal at a time when its staff produced an award-winning investigation that exposed fraudulent claims by the health care tech company Theranos.

On his watch, the paper was also at the forefront of reporting on payments involving President Trump and women who said they had once had sexual relationships with him. His tenure was also marked by unrest. In late-night emails, Baker accused editors of adding commentary to their coverage of Trump, and the staff pushed back, accusing him of going easy on the President.

More than a dozen journalists left the paper for The Washington Post and The New York Times. The Journal staff members’ criticism of their former boss came in the wake of the resignations of high-ranking editors at The Times.