It started off as a sex scandal, and it’s coming back around again.  The Washington Post reported last night that the FBI has expanded its probe of Senator Robert Menendez (D-NJ) beyond the interventions on behalf of big donor Salomon Melgen and his business interests, and into allegations that Menendez frequented prostitutes while traveling with Melgen to the Dominican Republic.  The scope of the investigation includes whether Menendez had contact with underage prostitutes:

A team of FBI agents has been conducting interviews in recent weeks in the Dominican Republic and the United States, looking into allegations that Sen. Robert Menendez (D-N.J.) patronized prostitutes in the Caribbean nation, but has found no evidence to support the claim, according to two people familiar with the investigation.

One person said agents have asked about whether a Florida eye doctor — a close friend and major campaign donor to Menendez — provided the senator with prostitutes on vacations there. Another person said investigators are looking into allegations involving underage prostitutes and sex parties.

The two, who spoke on the condition of anonymity to discuss an active investigation, said FBI agents are following leads provided by an unknown tipster. In a series of e-mails with the FBI, the tipster alleged that the doctor, Salomon Melgen, had made prostitutes available to Menendez while he was staying at his friend’s resort home in the Dominican Republic. The tipster, in particular, mentioned young prostitutes and prostitution parties.

This news vindicates the reporting earlier from the Daily Caller, although it doesn’t yet prove that Menendez is guilty of these allegations.  This story broke in the fall when Matthew Boyle (now with Breitbart) first reported on the anonymous tipster and interviewed two of the alleged prostitutes.  Menendez claimed that the story was invented by “right-wing blogs,” and other news outlets didn’t report on it — at least not until Menendez’ interventions on Melgen’s behalf with the Dominican Republic and Medicare got uncovered.

Now that the corruption scandal has finally become a sex scandal in the mainstream media, how long can Menendez hang on?  The Post explains what’s at stake:

Prostitution is not illegal in the Dominican Republic. But soliciting underage prostitutes is illegal. Also, a politician who accepts free gifts and special favors in exchange for official acts can face criminal prosecution for abuse of public office.

Legally, Menendez is presumed innocent until proven guilty. Politically, Menendez is starting to look like a big liability to Democrats, and with a Senate race coming up in New Jersey in 2014 for the state’s other seat, Menendez may start becoming toxic even in New Jersey, which traditionally has a high threshold of corruption.  Democrats may have to fight for two seats next year that they already have if this investigation gets any worse for Menendez, and the longer he sticks around, the worse it will be for Democrats in both races.