Sen. Robert Menendez, a Democratic Senator from New Jersey, has blamed the Cuban government for fabricating allegations that he slept with underage prostitutes. But that's not the interesting part of the Washington Post scoop on Menendez's request for the Justice Department to follow-up on his claim. This is the interesting part (emphasis ours): 

According to a former U.S. official with firsthand knowledge of government intelligence, the CIA had obtained credible evidence, including Internet protocol addresses, linking Cuban agents to the prostitution claims and to efforts to plant the story in U.S. and Latin American media.

The alleged Cuba connection was laid out in an intelligence report provided last year to U.S. government officials and sent by secure cable to the FBI’s counterintelligence division, according to the former official and a second person with close ties to Menendez who had been briefed on the matter.

Menendez, a Democrat, has a few political enemies. One of those is Cuba: he's been an outspoken critic of the dictatorship. Another is the conservative movement in the U.S. 

In November of 2012, the conservative news outlet the Daily Caller published a "scoop," sourcing two women, saying that Menendez had hired them for sex. As The Post notes, the FBI followed up but couldn't confirm those accounts. As it turns out, the Caller wasn't the only news organization contacted with similar information: ABC News talked to the same two Dominican women, plus a third woman, but declined to run with the story after they failed to confirm the identity of the sources (Poynter has more on the "unraveling" of that scoop, and the other media organizations who tried and failed to verify the Caller's reporting). All three women have since recanted their stories. According to The Post's source, the FBI themselves were contacted by a source using the pseudonym "Pete Williams" claiming to have information on the Senator's behavior in the Dominican Republic. 

It's really important to note here that the CIA's alleged evidence of the Cuban connection far from proves that the Caller was duped by a smear campaign. Speaking to The Post, the Caller's Carlson said  that he "really can’t assess it without more information,” adding, “It’s bizarre on its face, but also fascinating.” 

Menendez sent his letter in April, asking the Justice Department to follow up with the evidence. His claim, essentially, is that the story was timed as an attempt sabotage his political rise. Menendez remains under investigation by the Justice Department, who are pursuing allegations that the Senator used his office to benefit his friend, Salomon Melgen.