Madoff, 70, a former chairman of the Nasdaq stock exchange, was arrested Thursday in what prosecutors say was a multibillion-dollar scheme to defraud investors.
Mulhauser said the senator's investments with /*Bernard L. Madoff*/ Investment Securities LLC were primarily made through the Lautenberg family's charitable foundation, which donates to a variety of religious, educational, civic and arts organizations in New Jersey and elsewhere.
Mulhauser referred all further questions to Lautenberg's attorney, Michael Griffinger, who said in an e-mail Sunday afternoon that the extent of any losses was not yet clear as he had not had a chance to analyze paperwork related to the case that Sen. Lautenberg had just given him.
"The senator is obviously very distressed about the likely loss of the foundation funds in the hands of Madoff, and that the foundation will not be able to make contributions to the many charities it has served so well over the years," Griffinger said.
On Friday, Griffinger told The Record of Bergen County that the bulk of the Lautenberg foundation assets - nearly $14 million, according to 2006 filings - was invested with Madoff.
Lautenberg is one of the wealthiest members of the U.S. Senate. His family foundation handed out more than $765,000 to at least 100 recipients in 2006, according to the most recent listing on Guidestar, which tracks charitable organization filings.
Donations listed on the foundation's required financial forms range from $350,000 to the New Jersey-based United Jewish Federation Metrowest to a $2,000 donation to Hackensack University Medical Center's Tomorrow's Children Fund.
In addition to managing money for Lautenberg's foundation, Madoff was also a contributor to New Jersey political campaigns.
An analysis of election filings by The Record found that Madoff and members of his family connected to his firm have donated more than $400,000 to federal candidates in New Jersey since 1986.
Donations include $2,000 toward Jon Corzine's 2000 U.S. Senate run, $8,000 to former U.S. Sen. Bill Bradley in his 1999 campaign for president and $13,600 to Lautenberg's 2008 re-election campaign.
Speaking about Madoff's donation to Lautenberg, Mulhauser said, "We will be ridding ourselves of the contribution."
Lautenberg is among a growing list of prominent potential victims of the scheme in which Madoff allegedly took investments from one client to pay returns to another.
Those who have acknowledged potential losses so far include former Philadelphia Eagles owner Norman Braman, New York Mets owner Fred Wilpon and J. Ezra Merkin, the chairman of GMAC Financial Services, among others.