MONTREAL -- The Montreal Museum of Fine Arts' board has released an explosive letter condemning critics, some within the museum’s own administration, for speaking out against the firing of Director General Nathalie Bondil.

The former head of the Montreal Fine Arts Museum (MMFA) led a decades-long career as one of the city’s most recognized figures on the international art scene.

Bondil was fired after an internal investigation found her administration had failed to address several complaints of a poor working environment, according to the museum’s board.

Her dismissal was met with outrage by many, and not just in Quebec. Voices in the global art scene condemned what they saw as the dethroning of a central figure in the Canadian art world.

A petition was circulated in Bondil's favour, saying that “together, we have the fate of the MMFA in our hands. It's up to us to protect it.” More than 5,000 people have signed it.

Now, the museum says enough is enough.

The board released an official statement Friday condemning the outcry against Bondil’s dismissal both within and outside the museum.

“There comes a time when people must stop saying or writing nonsense,” reads the statement. “There comes a time when it becomes impossible to remain silent in the face of an endless stream of lies.”

The board makes specific mention of people within the organization itself. Governance expert Michel Nadeau, who is involved in the museum's foundation, spoke out in an open letter published in La Presse criticizing Bondil's firing and the process that led to it.

“How can one claim to be a defender of great principles of governance, like Michel Nadeau," today's statement said, "while ignoring the serious management problems within the walls of the Museum?”

The letter also accuses Board of Trustee member Joe Battat of lying about being present at a key meeting. A 90-page presentation was given outlining an external investigation into Bondil’s workplace habits, the letter says, and Battat was there at the time.

Like her supporters, Bondil has spoken out against the board’s description of her work and the reasons she was fired.

Shortly after her dismissal in July, Bondil said MMFA chairperson Michel de la Chenelière told her she was fired because she was “nitpicky.”

The board says that’s not true. “Ms. Bondil had lost the confidence of the Board and could no longer run the Museum,” they said.

The MMFA declined to comment.