A federal grand jury has been convened to examine the relationship between New Jersey Senator Robert Menendez and a Florida doctor in an episode which may end up doing as much damage to the reputation of the senator as to the conservative website that first published allegations against him.

According to the Washington Post, the grand jury last month began issuing subpoenas for the business records of Salomon Melgen, a ophthalmologist who has been linked to Menendez both personally and through campaign contributions. Among other things, investigators from the FBI have been looking into allegations that Melgen arranged prostitutes for the senator during trips to the Dominican Republic and Menendez's role advocating for a $500 million security contract for a company linked to the doctor.

Today's news is hardly a surprise, but, really, an escalation. It's been known that the FBI has been investigating the pair for months. According to the Post, the investigation was launched last year on two fronts simultaneously. At first, the FBI was investigating whether or not Melgen overbills Medicare for treatments. Then, last fall, the agency got an anonymous tip with the prostitution allegations.

Those allegations became public after the conservative blog The Daily Caller ran a story about the claims shortly before last year's election. The site picked up the story after several other news outlets declined to do so, arguing that evidence for the claims — statements from anonymous women — was too thin. The Daily Caller defended its story even after the Post suggested that one of the women involved in the accusations had recanted her statement.

This morning, the website of the liberal magazine Mother Jones reported that The Daily Caller's executive editor, David Martosko — the voice of that defense — admitted under oath to having used false Facebook identities to undermine animal rights groups. The admission came in a 2011 deposition as part of a defamation lawsuit filed against Martosko and his then-employer, a public relations company. Working with a group funded by food companies, Martosko admitted to creating fake Facebook profiles to pose as an animal rights activist in online discussions.

Shortly after that admission, which was not public at the time, Martosko was hired by Daily Caller founder Tucker Carlson. At the time of the hire, Carlson defended Martosko's criminal record, saying, "People who've been shamed in public tend to know themselves better, something I learned on Dancing with the Stars."

As executive editor, Martosko has not only defended the site's Menendez coverage, but also the site's 2011 claim that the EPA planned to hire 230,000 people — a story quickly and robustly debunked. Martosko recently announced that he is leaving the Daily Caller to become the Daily Mail's U.S. political editor. Whether or not this is a promotion is left as an exercise to the reader.