ARCA Founder Noah Charney and ISGM's Security Director Anthony Amore Talk about the largest art theft in US history and the hunt for the paintings 22 years later; NBC's "American Greed" to feature Gardner Museum Heist Tonight

Vermeer's "The Concert"

CNBC's Lindsay Nadrich (with Reuters contributing) writes about the 1990 robbery of the Isabella Stewart Gardner Museum online "22 Years Later, $300 Million Art Theft Investigation Heats Up."

Last week's search of the Connecticut home of an alleged Mafia member, 75-year-old Robert Gentile, with a ground-penetrating radar device found two guns but no artworks.

Noah Charney, Founder of ARCA, is quoted here.

"Vermeer's "The Concert" is probably the single-most valuable missing artwork today," art crime expert Noah Charney said.

Anthony Amore, author of Stealing Rembrandts and an instructor at the ARCA program in 2009, issued a statement to CNBC:

"While the Museum continues to thrive, the investigation into the 1990 theft remains very active," Anthony Amore, the Gardner's security director, said in a statement, "We will continue to work every day to recover the stolen masterworks.

To hear the full story of the Gardner Museum Heist, watch "American Greed" Wednesday at 10 p.m. ET/PT on CNBC (in the United States).