Over the past month, Dzhokhar Tsarnaev’s attorneys filed a flurry of motions in federal court, challenging various aspects of the government’s conduct pertaining to its investigation and handling of the marathon bombings. One of those motions called out the government for leaking confidential grand jury information to the press, and for current and former officials’ comments to the press about the case. The government’s leaks and comments to the press and the public “threaten Mr. Tsarnaev’s right to a fair trial,” the lawyers alleged, calling some of the leaks and statements “erroneous.”  The government shot back, boldly claiming there were no such leaks.

That’s why I was particularly confused to find that the DOJ, in a motion filed this week in the case, now claims that the bombs that exploded at the Boston Marathon were not built in Tamerlan Tsarnaev’s Cambridge apartment, and that officials found “virtually no traces” of explosive powder in the residence. Why was I confused? Unnamed officials’ leaks to the press in May 2013 assured us not only that the bombs were built in Tamerlan’s apartment, but also that the government had forensic evidence to prove it! Further, an unnamed source told CNN that the younger Tsarnaev confessed to having built the bombs with his brother in the apartment! Surely only the FBI and prosecutors working on the case would know such a thing, right?

Here’s part of a CNN story from May 6, 2013:

On Friday, a source briefed on the investigation said investigators found explosives residue in the small apartment.

It has turned up in at least three places, the source said: the kitchen table, the kitchen sink and the bathtub.

Tsarnaev’s younger brother, Dzhokhar Tsarnaev, has said they built the bombs there, U.S. law enforcement officials briefed on the progress of the investigation said.

Here’s another CNN story, this one dated three days prior, May 3, 2013:

The bombs used in the Boston Marathon attack were built in the apartment that suspect Tamerlan Tsarnaev shared with his wife and child, a U.S. law enforcement official with first-hand knowledge of the investigation told CNN on Thursday. The official was not authorized to release the information.

The same CNN story later attributes another claim about the Tsarnaevs to “two federal law enforcement officials.”

That was in May 2013. Now look at the DOJ’s statements about the same issue in May 2014, from a DOJ motion in the Tsarnaev trial:

“[S]earches of the Tsarnaevs’ [sic] residences, three vehicles, and other locations associated with them yielded virtually no traces of black powder, again strongly suggesting that others had built, or at least helped the Tsarnaevs build, the bombs.“

That sounds very different from the claims anonymously leaked to CNN by the “US law enforcement official with first-hand knowledge of the investigation” in May 2013, who said that the bombs were built in the apartment.