But judges have repeatedly dismissed the lawsuits, most recently in 2010 when a U.S. appellate court ruled against Melgen. He tried again last July, filing a new case against Bank of America.
The Senate Majority Leader, Harry Reid of Nevada, urged Menendez to stop publicly discussing his business relationship with Melgen, a Florida ophthalmologist and entrepreneur. Reid cited a pending inquiry into the matter by the Senate Ethics Committee but praised Menendez as an invaluable leader.
"We all have these issues come to us," Reid said. "We have to work our way through it ... I would suggest to my friend that he shouldn't get into this today."
Menendez has acknowledged that he flew on Melgen's private plane and failed, initially, to properly pay for the trips. He told reporters he reimbursed some $58,500 from his personal funds.
Melgen has recently requested that online flight-tracking services block records showing the history of his plane's travel. Those flight reports, which had been publicly available as recently as this week, had logged the times and locations of his Canadair CL-600's arrivals and departures since he acquired the aircraft in July 2009. The Federal Aviation Administration allows aircraft owners and operators to request flight-tracking information be blocked from the public.
The events have engulfed Menendez, 59, just as he assumed the chairmanship of the Senate Foreign Relations Committee, succeeding former Sen. John Kerry, D-Mass., who resigned last week to become secretary of state.
Melgen has been a friend and political supporter of Menendez's for many years. Last year, Melgen's practice gave $700,000 to Majority PAC, a super political action committee set up to fund Democratic candidates for Senate. Aided by Melgen's donation, the super PAC became the largest outside political committee contributing to Menendez's re-election, spending more than $582,000 on the senator's behalf.
Kennedy reported from Miami. Associated Press writers Stephen Braun, jack Gillum and Andrew Taylor also contributed from Washington.
Contact the Washington investigative team at DCinvestigations (at) ap.org