Federal agents raided the West Palm Beach eye clinic of a longtime friend and political supporter of Sen. Robert Menendez earlier this week after a document shredding truck was observed at the building, following attempts by FBI agents to question Dr. Salomon Melgen about his relationship with the New Jersey Democrat, according to federal officials familiar with the investigation.
The execution of the search warrant was carried out by a federal health care task force, with agents from both the FBI and the federal Department of Health and Human Services Inspector General's office, which had been investigating suspected Medicare fraud by Melgen's clinics for more than a year, the sources told ABC News. The raid appeared unrelated to recent allegations regarding Menendez's trips to Melgen's home in the Dominican Republic.
An attorney for Dr. Melgen's office told ABC News that "the government has not informed Dr. Melgen what concerns it may have. We are confident that Dr. Melgen has acted appropriately at all times. "
A spokesperson for Sen. Menendez told ABC News Thursday that the Senator's office was unaware of any FBI investigation or inquiries involving the Senator. The spokesperson confirmed the Senator was a longtime friend of Dr. Melgen and had recently reimbursed Melgen $58,000 for three trips on the doctor's private jet to the Dominican Republic, following a complaint to the Senate Ethics Committee by a Samuel Thompson, a New Jersey state senator and chair of the Middlesex County Republican Organization, in November 2012, just days prior to Menendez's reelection.
The spokesperson said the Senator was advised by Democratic campaign finance attorneys that under the "friendship" exclusion he likely didn't need to reimburse the cost of the trips, but to avoid any questions of impropriety decided to repay the full cost.
The spokesperson for Menendez also strongly denied allegations by The Daily Caller website that Menendez was involved with underage prostitutes during those trips.
"All of these allegations from a right-wing blog of engaging in prostitution are absolutely false," said the spokesperson. "The Senator has known Dr. Melgen for years and his travel on Melgen's plane on three occasions has been reported and reimbursed as required by the rules."
A spokesperson for the FBI would not confirm or deny the existence of an investigation. The HHS did not immediately respond to a request for comment.
Melgen, an eye doctor, is a major political donor, with most of his money going to Democrats. Over the past two decades, he and his family have contributed more than $400,000, and nearly $50,000 has gone to Menendez and Menendez PACs. They also contributed $60,400 to the Democratic Senatorial Campaign Committee in 2009 – Menendez chaired the DSCC from 2009 to 2011 – and $50,000 to the New Jersey Democratic State Committee.
Questions about Menendez and his relationship with Melgen were raised by a pseudonymous tipster who contacted the Washington, D.C. good government group Citizens for Responsibility and Ethics in Washington (CREW) in 2012.
The tipster, using the name Peter Williams, told CREW via email that Menendez had traveled to the Dominican Republic in Melgen's plane and had had sex with prostitutes, at least one of them underage.
"There's reason to be quite skeptical of these allegations," said Melanie Sloan, executive director of CREW. "Mr. Williams claims to have known about the Senator's conduct since as early as 2008 yet didn't come forward for four years until right before Menendez's reelection."
"In addition, despite efforts by Crew, news organizations and the FBI to speak with Mr. Williams either by phone or in person, he's refused to do that for over eight months," said Sloan. She said CREW was unable to determine if the underage woman referenced by Menendez was "a prostitute, underage, or even real."
"The timing, combined with his insistence on remaining on communication only through email, seriously undermines the credibility of the allegations," said Sloan.
Earlier this week, dozens of emails between "Peter Williams" and CREW, ABC News and the FBI were published on a website.
Despite extensive efforts by ABC News to meet with Williams, speak with him on the phone, or verify his identity, Williams refused to come forward.