President Trump attacked CNN on Wednesday, writing on Twitter that the network had been “caught in a major lie” in connection to an article it published in July about claims made by the president’s former personal lawyer, Michael D. Cohen.

The article, which was written by Jim Sciutto, Marshall Cohen and Carl Bernstein, the high-profile Watergate reporter, said Mr. Cohen was claiming that Mr. Trump knew in advance about a now infamous June 2016 meeting at Trump Tower in which Russians were expected to offer damaging information on Hillary Clinton.

The special counsel, Robert S. Mueller III, is investigating possible links between the Trump campaign and Russia’s election interference.

In the meantime, a flurry of statements in recent days from Mr. Cohen’s lawyer, Lanny J. Davis, has, for some, muddied the water around the sourcing and validity of CNN’s report. In essence, Mr. Davis has admitted he was an unnamed source for the article, and has backed away from the claims he made about Mr. Cohen. (More on this later.)