Defense attorney David Bruck today told a federal court that what authorities have described as a central piece of the prosecution’s evidence against his client “does not exist.”

In the aftermath of the Boston Marathon bombings, public officials including the former Special Agent in Charge of the Boston FBI office Richard DesLauriers and the former governor of the state of Massachusetts told the public about a “chilling” video that all but proved the young Dzhokhar Tsarnaev’s guilt. Speaking on NBC’s Face the Nation, Governor Deval Patrick said the video shows Tsarnaev placing a backpack down and walking away, just before it explodes.

“It does seem to be pretty clear that this suspect took the backpack off, put it down, did not react when the first explosion went off, and then moved away from the backpack in time for the second explosion,” the two-term Massachusetts governor said. “It’s pretty clear about his involvement and pretty chilling, frankly.”

Later Governor Patrick disclosed that he had not seen the video.

During jury selection in the Tsarnaev case, a potential juror told Judge O’Toole that she thought she could be fair and impartial, even though she couldn’t get the image of Tsarnaev putting the bomb down out of her head. “The image of him putting the backpack behind that little boy…I do have this image in my mind that I can’t deny, to be perfectly honest,” she told the court, describing what authorities have said is a video showing Tsarnaev leaving the backpack at the scene.

In a February federal appeals court hearing on a defense motion to move the trial out of Boston, both a federal judge and a DOJ prosecutor referenced the public airing of the video showing Tsarnaev placing the backpack on the ground.

The video has never been aired publicly.

Now Tsarnaev’s defense team has said in open court that it doesn’t exist.