An investor and self-proclaimed victim in Bernard Madoff’s Ponzi scheme sold an art collection filled with Mark Rothko paintings for $310 million last month, and some of the details of the transaction are raising questions — particularly who the seller’s agent is.

J. Ezra Merkin’s involvement with Madoff brought him a loss of $3.4 million in a charitable trust and more than $10 million in personal funds. On top of that, he’s being sued by New York State Attorney General Andrew Cuomo for concealing his $2.4 billion investment with Madoff; the suit wants Merkin’s art collection and other assets to compensate his many wiped-out investors. What’s surprising some art dealers is that the artworks’ sale to a still-unknown buyer generated $37.5 million in fees, with the unidentified agent receiving a sizable $26.5 million. Court documents name the agent only as TLIA, LLC, which is registered in Connecticut to a retired art collector and adviser named Ben Heller.

Heller isn’t commenting, but his connection to Merkin is well known: From 2003 to 2008, he helped the financier and his wife assemble the largest private Rothko collection in the world. He even arranged special lighting and wall tones to complement the collection in the Merkins’ Park Avenue apartment. Until Cuomo’s suit is resolved, money from July’s sale, which produced $191 million after fees, taxes, and legal expenses, will be held in escrow.