J. Scott Applewhite / AP

Sen. Robert Menendez, D-N.J.

U.S. Sen. Robert Menendez this month wrote a $58,500 check to a company owned by a South Florida eye doctor and political fundraiser to reimburse him for two personal flights to the Dominican Republic that the New Jersey Democrat did not report on his Senate financial disclosure form, his office confirmed to NBC News Wednesday night. 

The disclosure came as law enforcement sources confirmed that FBI agents searched the West Palm Beach, Florida, offices of the doctor, Salomon Melgen, Tuesday night as part of an investigation that includes agents from the Department of Health and Human Services.

Melgen is a major Democratic political donor and fundraiser who together with family has contributed more than $200,000 to Democratic candidates, including $33,000 to Menendez. 

Menendez’s office confirmed that the senator — who this week became chairman of the Senate Foreign Relations Committee – wrote the check to Melgen from his personal account after aides reviewed his flight schedule in response to a complaint that a New Jersey Republican official filed with the Senate Ethics Committee last November. The complaint alleged that Menendez violated Senate Ethics rules by “repeatedly flying on a free jet to the Dominican Republic and other locations” and that the jet was provided by Melgen. 

“This was sloppy,” Dan O’Brien, Menendez’s chief of staff, told NBC News about Menendez’s failure to pay for the two 2010 flights at the time. “I’m chalking it up to an oversight.” Asked whether the senator has been contacted by the Senate Ethics Committee about the matter, O’Brien responded: “We can assume the Senate Ethics Committee is looking at the allegation. ”

O’Brien provided new details about Menendez’s relationship with the Florida doctor amid a swirl of media reports about the FBI probe. He said Menendez and the doctor have been longtime personal friends and that the senator has visited Melgen at his home in the Dominican Republican “about twice a year,” including attending Melgen’s daughter’s wedding. He said Menendez has generally flown commercial for those flights and paid for them out of his own pocket.

He confirmed that Melgen has also been an active fundraiser for Menendez, holding events for him at his home in South Florida as well as at a home he owns in Caso de Campo, a Dominican resort.

All told, the senator took three flights aboard Melgen’s jet in 2010 — one of which that May involved a trip to Puerto Rico and the Dominican Republican for political fundraisers, O’Brien said. One of those fundraisers was at Melgen’s home in the Dominican Republic, O’Brien said. The May 2010 flight for fundraisers on the two islands was paid for at the time by the Democratic Senatorial Campaign Committee, which Menendez then chaired. 

But after the ethics complaint was filed Nov. 3, his aides conducted what they described as an “exhaustive review of Menendez’s schedule” and found that the senator had taken two additional flights aboard Melgen’s corporate jet. One, from Aug. 6 to Aug. 9, 2010, was from south Florida to the Dominican Republic and back to south Florida. Another was from Sept. 3 to Sept. 6, 2010, was from Teterboro Airport in New Jersey to the Dominican Republican and back to New Jersey. In at least one of those flights, Menendez brought along guests, O’Brien said.

O’Brien said that after the review — spurred by the ethics complaint — Menendez wrote the $58,500 to Melgen’s company from his personal account. Under Senate ethics rules, senators are allowed to accept gifts from personal friends, but any valued at more than $250 must be publicly reported and approved by the Senate Ethics Committee.

In a statement earlier Wednesday, Menendez’s office said that: “Dr. Melgen has been a friend and political supporter of Senator Menendez for many years. Senator Menendez has traveled on Dr. Melgen’s plane on three occasions, all of which have been paid for and reported appropriately.”

That statement made no reference to Menendez paying for the trips in January, two months after the ethics committee complaint was filed. Asked about the omission, a spokeswoman for the senator said: “There was never any intention to be misleading.”

The spokeswoman said the senator was not aware of any time requirement for reimbursing for personal trips. She also said Menendez, by reimbursing for the flights, was not claiming the trips aboard Dr. Melgen’s plane was a personal gift. Although personal gifts above $250 need ethics committee approval, Menendez was not claiming the flights as a gift  and therefore does not need to seek approval of them from the committee, the spokeswoman said.