But FBI agents were actually interested in Grimm's failure to file paperwork related to his trip to Cyprus following his Israeli junket, which had been paid for by the Cyprus Federation of America. The president of that company was arrested on federal corruption charges in June. Grimm had reported the Israel trip in his initial filing in May but did not list the trip to Cyprus until he amended it in June, one day after Cyprus Federation of America's president was arrested.
FBI agents may have asked questions about "who went into the water that night, and whether there was any impropriety," as Politico reported, but sources indicated the dip in the water certainly wasn't the FBI's central focus.
Grimm's office did not comment about the incident to the Staten Island Advance, but "confirmed that Yoder was the only congressman who swam nude," according to the paper.
Grimm, a former FBI agent, has been the subject of plenty of attention from federal authorities over the past year. On Friday, one of Grimm's top fundraisers was arrested for allegedly lying about the source of a loan on immigration documents. That man, an Israeli named Ofer Biton, traveled around the New York area with Grimm in 2010 to raise money for his congressional campaign. At least four of Grimm's 2010 campaign workers have been questioned by the FBI. Federal prosecutors have also interviewed several donors, according to the New York Times.
While congressional ethics travel rules passed in 2007 ban entities that employ lobbyists from paying for trips that last more than one day, the Israel trip appears to have taken advantage of a loop-hole that allows lobbying companies to set up connected 501(c)(3) entities to pay for trips.
Late update: The Wall Street Journal's Devlin Barrett and Danny Yadron confirm our report:
The person familiar with the investigation said the FBI came across details of the swimming incident while examining the Israel trip and a trip Rep. Grimm made afterward to Cyprus, but that the swimming incident wasn't relevant to the probe.