NEW YORK -- Politico senior congressional reporter John Bresnahan investigated prostitution allegations against Sen. Robert Menendez (D-N.J.) before a Nov. 1 report in the Daily Caller suggesting they were true, according to a source with direct knowledge of the situation.

Many prominent news organizations did not follow up on the Daily Caller's report, which featured two women in the Dominican Republic, faces obscured, claiming on video to have had sex with Menendez for money. This week, reports from the Washington Post and ABC News raised new questions about the credibility of the sources used by the Daily Caller, which continues to stand by its reporting.

When reached by phone on Friday, Bresnahan referred The Huffington Post to Politico COO Kim Kingsley, who did not return a request for comment. A Politico spokeswoman declined to comment.

It was also revealed this week that political operatives approached several news organizations -- including ABC News, the New York Post, and the New Jersey Star-Ledger -- with the allegations prior to the Daily Caller's report. All three news outlets investigated the charges, but found no evidence to back them up or justify publishing a story.

On Wednesday, ABC News revealed that "GOP operatives helped to arrange Skype interviews in the Dominican Republic with three women who all told ABC News the Senator paid them for sex” and “two of the women repeated the claims to a conservative news website, the Daily Caller.”

ABC News explained that it did not publish a story based on the claims because "none of the women could produce identity cards with their names, and they all provided the same story almost word for word, as if they had been coached."

The Huffington Post reported Friday that the New York Post's Josh Margolin and the Star-Ledger's Ted Sherman also were approached by operatives with the prostitution allegations last summer and investigated them. Neither Margolin nor Sherman -- each veterans of past New Jersey political scandals -- found legitimate information that would merit a story.

Bresnahan recently hinted in a Feb. 16 article on an FBI probe of the allegations that Politico may have investigated the claims. Bresnahan wrote that an "anonymous contact has declined to identify himself in exchanges with POLITICO and other organizations looking into the allegations against Menendez going back to last year."