Zens is the corporate version of a questionable tax shelter known as Cards, which is at the center of the criminal inquiry of Deutsche Bank.
The transaction at the centre of the inquiry was named the "Magnum" transaction after the EPI company involved.
Mr. Dillon is at the center of the inquiry, investigators said.
The foundation at the center of the federal inquiry first came under scrutiny in early 2003, after an article in The Daily News raised questions about its finances.
Hundreds of millions of dollars in Kremlin work went to a Swiss company, Mabetex, which is at the center of the inquiry.
Executive Continental's role at the center of the federal inquiry was first reported on Sunday by The Home News Tribune.
In addition to Mr. Fisher, Preston Semel, a large broker with several of the exchanges, has been said to be at the center of the inquiry.
They say she did not represent Madison Guaranty, an Arkansas savings and loan at the center of the inquiry, before state regulators while her husband was Governor.
Today, he sits near the center of the inquiry into whether Pakistan's nuclear secrets were transferred to Libya and Iran in the late 1980's.
At the center of the inquiry is a construction company called Mabetex, which received a portion of the lucrative contracts for repair work in the centuries-old Kremlin.