(ORLANDO, Fla.) -- The director of a Florida art museum has been ousted amid a federal investigation into the authenticity of more than two dozen paintings purportedly by the late artist Jean-Michel Basquiat that were on view in the institution's blockbuster show.
The exhibition, "Heroes and Monsters," at the Orlando Museum of Art, has been under scrutiny since a New York Times report published upon its opening in February raised questions about the authenticity of the pieces, including one that featured a FedEx cardboard shipping box with a typeface that an expert said wasn't used until after the artist's death in 1988.
On Friday, days before the exhibition was scheduled to end, the FBI Art Crime Team based out of Los Angeles executed a federal search warrant at the museum as part of a federal investigation, an FBI spokesperson said.
According to an affidavit in the search warrant to seize the 25 paintings, the FBI is investigating alleged conspiracy and wire fraud in connection with the artwork. The pieces were purportedly created in 1982 and found in a storage locker owned by the late TV producer Thaddeus Mumford, Jr. whose contents were sold at auction in 2012.
In an interview with the FBI in 2014, four years before his death, Mumford denied ever having any Basquiat artwork and was unaware of the artist's work being stored in his storage locker, according to the affidavit. Several experts who spoke with the FBI agent also "have opined that the artwork is not authentic," the affidavit stated.
The affidavit included an email sent by the museum's ousted director and CEO, Aaron De Groft, to an art professor paid $60,000 by the owners of the artwork to assess several pieces who was requesting that her name not be associated with the exhibition.
"Shut up. You took the money. Stop being holier than thou," De Groft wrote, according to the affidavit. "Be quiet now is my best advice. These are real and legit. You know this. You are threatening the wrong people. Do your academic thing and stay in your limited lane."
On Tuesday, Cynthia Brumback, chair of the Orlando Museum of Art's Board of Trustees, announced that De Groft is no longer director and CEO of the museum "effective immediately."
"The Orlando Museum of Art's Board of Trustees is extremely concerned about several issues with regard to the 'Heroes and Monsters' exhibition, including the recent revelation of an inappropriate e-mail correspondence sent to academia concerning the authentication of some of the artwork in the exhibition," Brumback said in a statement.
ABC News did not immediately hear back from De Groft for comment.
The highly anticipated museum exhibition garnered crowds eager to see the paintings, even while their authenticity was under question. Museum attendance went up 500% since the exhibit went on display, ABC Orlando affiliate WFTV reported.
Amid the controversy, Brumback said Tuesday that the museum has "launched an official process to address these matters, as they are inconsistent with the values of this institution, our business standards, and our standards of conduct."
Prior to the FBI raid, De Groft defended the exhibition.
"We stand by our industrial, rigorous, academic process," he told reporters in February. "They were authenticated before we were involved by major, major specialists that put their entire reputations on the line.”
The authenticity of at least one of the pieces is called into question over the inclusion of a FedEx logo, according to the affidavit.
"Forensic information indicates that the cardboard on which one painting was made contains a typeface that was created in 1994, after Basquiat had passed," the affidavit stated.
As part of its investigation, the FBI has uncovered attempts to sell the paintings "using false provenance," and what appear to be investments via wire transfer in "artwork that is not authentic," according to the affidavit.
The investigation is ongoing and no charges have been filed yet, a spokesperson for the U.S. Attorney's Office for the Central District of California told ABC News Wednesday.