It seems every day brings a fresh revelation of another Jeffrey Epstein “friend.” Just this week, old photos emerged showing Sarah Ferguson and Chris Tucker and even Hilary Swank posing with Epstein’s maid or her husband. From Wall Street to Park Avenue, from M.I.T. to Windsor Castle, those at or near the top are holding their breath, wondering what new piece of evidence will bubble up and pull them, rightfully or not, into the Epstein morass.

One of them must surely be private-equity billionaire Leon Black. He’s not a bold-faced name like Prince Andrew or Bill Clinton. But he’s still the kind of person (hyper-rich) that Epstein attracted. As the co-founder and C.E.O. of Apollo Global Management, the behemoth private-equity-and-asset-management firm, he has a fortune of around $8 billion (and growing).

Despite Black’s by now well-documented ties to Epstein, people invested in Apollo’s publicly traded stock seem indifferent to the scandal. In fact, the public stock of Black’s company keeps hitting one all-time high after another. This is partly explained by the decision to convert Apollo to a corporate structure, a move made by other moguls in the private-equity industry. And by his proven 30-year track record of being a superb investor.

Wondering what new piece of evidence will bubble up and pull them, rightfully or not, into the Epstein mess.

Outwardly, Black doesn’t seem fazed by the scrutiny. He continues to be out and about in Manhattan and on Long Island (where he owns expensive homes). Over Labor Day, he and his wife attended a party given by Joel Klein, the former schools chancellor under Michael Bloomberg, and his wife, Nicole Seligman, a high-powered attorney.

Maybe it’s all no big deal. But Epstein’s reported suicide in August does not mean the inquiries end. In fact, the public seems more curious than ever about the people Epstein collected and why they were so willing to be associated with someone like him.

Black at a Sotheby’s dinner in 2017.

There’s a seismic shift going on in the social order—with the Sackler family, of OxyContin infamy, being Exhibit A. The richest people are now shrouded in mistrust. Yet Black—who has so much at stake and quite a few questions to answer—has been quiet.

And that has people talking. If, as is increasingly obvious, Epstein was not at all a financial genius, why would Black—arguably one of the savvier investors on Wall Street—continue to associate with a make-believe Wall Street outsider who went to jail in 2008 for sex crimes? Did anyone really “need” Epstein’s wealth or brains? Or was it something else that drew people like Black, L Brands’ C.E.O. Les Wexner, and hedge-fund billionaire Glenn Dubin into Epstein’s orbit?

Mystery Ties

And then there are other questions. Among them:

• Well after Epstein had been convicted of sex crimes involving minors in 2008, why did Black keep him on as a director of his family foundation? (Black’s foundation has said in the past that it was a clerical error.)

• Well after Epstein did time in prison, why did Black invite him to a party at his family’s $43 million Hamptons house in 2015, according to the New York Post? (The article about Epstein in this issue recounts that in 2013, Black’s arrival at Epstein’s town house was announced this way: “Leon’s here.”)

• Why did Black dispatch Mark Rowan, one of the three founders of Apollo, to meet with Epstein at his Manhattan mansion in 2015 to see how Apollo might work with the Edmond de Rothschild Group, an investment consortium, with Epstein supposedly making the introduction? (This according to Bloomberg, but denied by all parties.)

Or was it something else that drew people like Black, L Brands’ C.E.O. Les Wexner, and hedge-fund billionaire Glenn Dubin into Epstein’s orbit?

• Why, in 2011, did Black, his four children, and Epstein all invest together in a company—Environmental Solutions Worldwide—that makes emissions-control products? And why did two of Black’s sons serve on its board of directors?

• Why exactly did Black, at Epstein’s request, donate $5.5 million to the now tainted M.I.T. Media Lab?

To be fair, Black has done some explaining. In a July e-mail to employees Black said that “from time to time Mr. Epstein has provided professional services to my family partnership and related family entities, involving tax, estate planning and philanthropic advice.”

Why exactly did Black, at Epstein’s request, donate $5.5 million to the now tainted M.I.T. Media Lab?

Oddly, Black ended by apologizing for the media distraction and angling for absolution for a relationship with Epstein he claims he never had. “Most important,” Black said, “I was completely unaware of, and I’m deeply troubled by, the conduct that is now the subject of federal criminal charges brought against him.”

He wrote a similar message to Apollo’s limited partners. One of them, though, the California Public Employees’ Retirement System (known as CalPERS), which has around $1.7 billion tied up in Apollo’s various funds, has stepped up its scrutiny of Black’s relationship with Epstein.

“CalPERS takes this issue very seriously,” Megan White, a spokeswoman for the pension fund, told Pensions & Investments magazine in an e-mail. “The actions our general partners take, both in professional and private contexts, impact our assessment of which firms we desire as long-term partners.”

Another Suicide

Scandal has touched Black before. Born in 1951, he grew up in Westport, Connecticut, the son of a prominent businessman father and an artist mother. His father, Eli Black, emigrated from Poland in the 1920s and graduated first in his class from Yeshiva University. He became a rabbi and also owned United Brands Company, the banana importer (now known as Chiquita) that throughout much of the 20th century had sketchy business practices in South America.

In February 1975, when his son was in his final year at Harvard Business School, Eli Black locked the front doors to his company’s office on the 44th floor of the Pan Am Building, on Park Avenue, smashed a hole in a window with his briefcase, and leapt to his death. He left no note. He was 53 years old. As The New York Times reported, he had been “under great strain because of business pressures.” (Investigators later discovered that Eli Black was connected to a Honduran bribery scandal.)

On the 44th floor of the Pan Am Building, Eli Black smashed a hole in the window with his briefcase and leapt to his death.

Black told The New York Times around two weeks after his father’s death that, the weekend before the suicide, the family had gone out to dinner. “On Sunday, I cooked him an omelet for breakfast. He was low. At dinner Saturday he wasn’t as ebullient as he usually was at family meals.” During a subsequent walk, “he kept complaining about the economy, the Government, Israel and energy,” his son said.

Junk-Bond Bonanza

There’s been no suggestion that his father’s suicide prompted Leon Black to become his family’s breadwinner. But he has become that, and then some. After getting his M.B.A., he landed a job at Drexel Burnham Lambert, the investment bank made famous by Michael R. Milken and his extraordinary high-yield debt operation. Black eventually ran Drexel’s M&A group and was a close associate of Milken’s. Drexel blew up in 1990, and Milken went to prison for securities fraud and illegal trades. But Black and his two younger partners, Marc Rowan and Joshua Harris, walked away clean. They famously bought a $3 billion bond portfolio from Executive Life, a Drexel junk-bond client, at a 50 percent discount to its face value. They made a killing. The three Apollo founders are all multi-billionaires now.

Milken went to prison for securities and tax violations. But Black and his two younger partners, Marc Rowan and Joshua Harris, walked away clean.

In the past 30 years or so, Black has gained a well-deserved reputation for being a canny buyer and seller of companies, usually picking up the properties at a discount, turning them around, and selling them for a big profit. Apollo, which went public in March 2011, has more than $300 billion under management and a market capitalization of around $16.3 billion. Apollo has been on a tear buying up local television stations and recently agreed to provide $1.8 billion of debt financing for New Media Investment Group’s announced acquisition of Gannett, in a bid to create the nation’s largest newspaper chain.

All of which has made Black very wealthy, powerful, and utterly inscrutable. But in a time when every philanthropic gift seems to get second-guessed, one can only wonder if his contributions could eventually be Sacklered. In addition to donating $48 million to Dartmouth and $7.5 million to Harvard, he has also donated some $40 million to create the Melanoma Research Alliance, after his wife was diagnosed with the disease. (To add to the intrigue, Harvard admitted on Thursday that it had received $9 million in gifts from Epstein in the years before his guilty plea.)

The Art Market

The Blacks are among the world’s top 200 art collectors, according to ARTnews. Leon Black is the chairman of the board of the Museum of Modern Art. Last November, the couple donated $40 million to MoMA’s renovation, and a new film center will bear their name. The Blacks collect a variety of artworks, but Black is probably best known in the art world for paying, in 2012, nearly $120 million, a record at that time, for Edvard Munch’s 1895 pastel drawing The Scream.

Black at the Calder Foundation in 2014.

One longtime friend from New York City, who also knows him from Vail, during the days when Apollo owned the ski resort, says that although Black “may be churning like a volcano inside,” he is “publicly stoic” and that “nothing really fazes him,” not even the Epstein scandal. “He’s the sort of guy who’s been through so much good, bad, and sideways in terms of his father, his career, and being buffeted by winds in every direction,” the friend continues. “My guess is that something tangential like this, I can’t imagine he’d let it get to him.”

On the other hand, this friend, like others, admits he is baffled by the connection. “Nobody’s explanation of their relationship with Epstein makes sense,” he says. “I’ve never heard anyone articulate a piece of wisdom that Epstein imparted that would warrant the magnitude of people’s relationship or beneficence or anything else toward him. You’re always thinking there is something else going on here.”

“Nobody’s explanation of their relationship with Epstein makes sense.”

There was, however, a revealing e-mail about Black included in a New Yorker story about his $5.5 million donation to the M.I.T. Media Lab. In an e-mail, Peter Cohen, who was then the Media Lab’s director of development and strategy, asked Joi Ito, the recently resigned Media Lab’s director, whether Black wished his contributions made through Epstein to M.I.T. to remain anonymous. Cohen wrote, “Can you ask Jeffrey to ask Leon that?” He added, “We can make it anonymous easily, unless Leon would like the credit. If Jeffrey tells you that Leon would like a little love from M.I.T., we can arrange that too … ”

Maybe, in the end, Leon Black just wanted a little love.

William D. Cohan is based in New York and is most recently the author of Four Friends: Promising Lives Cut Short