Billionaire art dealer Helly Nahmad's gallery was raided by the FBI on Tuesday morning. A longtime tenant at the Carlyle Hotel on Madison Ave., the gallery was searched by the feds as part of a sweep of illegal gambling rings operated by Russian organized crime, Forbes reports.

Heir to an art dealing fortune, with family patriarch, David, listed by Forbes to be worth $1.75 billion as of last month (down from $3 billion in 2011), Helly Nahmad has not been named as one of the dozens who were arrested around New York and elsewhere in the U.S. during the massive sweep.

Feds are investigating an extensive network of sports-betting and high-stakes poker dens frequented by the rich and powerful.

Forbes updated the story with an announcement from the U.S. Attorney for the Southern District of New York alleging that one of the enterprises in the scheme laundered tens of millions of dollars through Cyprus shell companies and bank accounts.

Helly Nahmad's connection to the probe has not yet been made public.