On March 25, 2015, prosecutors opened their arguments in US v. Tsarnaev by introducing an “interactive diagram” of Tamerlan Tsarnaev’s Norfolk Street, Cambridge apartment. 21 year-old Dzhokhar Tsarnaev’s defense counsel immediately objected to the caption on the diagram, which identified the apartment as Tamerlan and Dzhokhar Tsarnaev’s residence. Judge O’Toole sustained the defense objection, but allowed the diagram into evidence. He instructed the jury to ignore the caption.

At issue in this seemingly innocuous courtroom disagreement is an important question: At the time of the attacks, did Dzhokhar live in Cambridge with his brother’s family, or at UMass Dartmouth, where he was a student? The answer has significant ramifications for the case.

If the DOJ is able to convince jurors that the younger Tsarnaev did share the Norfolk Street residence, prosecutors might also be able to convince them that the items the FBI found there could have belonged to Dzhokhar—the sole person charged in the bombings after the violent death of his brother in April 2013. And if prosecutors can get the jury to believe that the soldering iron, pressure cooker lid, wiring, and shrapnel found in the Norfolk Street home were Dzhokhar’s, they might also be able to convince jurors that he was a driving force behind the attacks, not simply an impressionable accomplice. If the jury believes the former, it will be easier for them to sentence Jahar to death.

Last week in court, as prosecutors geared up to introduce evidence from the apartment, Judge O’Toole told the jury to discount the DOJ’s labeling of the Norfolk Street home with Dzhokhar’s name. But in the hours and days that followed, prosecutors seemed hell-bent on convincing the jury that the apartment—and therefore anything in it—belonged to the whole Tsarnaev family, the young college student included. O’Toole let this happen. The DOJ admitted lots of seemingly incriminating evidence from the Norfolk Street house. Reporters live-tweeting the proceedings commented on how the DOJ was hammering home the idea that Dzhokhar lived at Norfolk Street. The inference DOJ was trying to draw was clear: any items found in the Norfolk Street house belonged to the young Jahar as much as they belonged to the elder Tamerlan. Whatever they found there—which apparently included the contents of a kitchen junk drawer and a pickle jar with some nails in it, both introduced into evidence—could be used to find the little brother guilty and issue him a death sentence.

But there’s a glaring problem with this line of argumentation: The DOJ itself said the exact opposite in the same trial just a year ago.

'That was then, this is now—wait, we meant what we said before'

On May 7, 2014, the Tsarnaev defense team filed a motion to suppress evidence the FBI seized from the Norfolk Street apartment and Dzhokhar’s UMass dorm room, citing the warrant applications’ lack of particularity and other problems. On June 3, 2014, Massachusetts Assistant US Attorney Aloke Chakravarty filed an opposing motion in which the government asserted that the defendant "lacks standing to challenge the search and seizure of items from the Norfolk Street apartment."

"To establish standing," the government wrote, "Tsarnaev must show that he, personally, had a privacy interest in the Norfolk Street apartment or a possessory interest in the items that were seized."

Back in June 2014, when it was convenient for them, DOJ prosecutors said "Tsarnaev lost his expectation of privacy in the [Norfolk Street] apartment when he moved out" [emphasis mine]. Last year, in their brief to the court, prosecutors provided all sorts of evidence to show that the young Dzhokhar did not live at the Norfolk Street residence and therefore didn’t have standing to challenge the legality of government searches of the apartment.

He did not pay rent and was not on the lease.  Although he was raised in the apartment, he moved out in September 2011 after he became an adult, enrolled at UMass-Dartmouth, and leased a dorm room there, for which he paid rent….

[Katherine and Tamerlan Tsarnaev] slept in the apartment every night and kept all of their clothing and belongings there. Tsarnaev, in contrast, slept nearly every night in his dorm room at UMass-Dartmouth and kept virtually all of his clothing and belongings there….Tsarnaev was only an occasional overnight guest in the Norfolk Street apartment and kept only a few belongings there, and was not staying there overnight at the time of the search….His old bedroom had effectively become an extension of the living room and was used by Tamerlan Tsarnaev’s family as a storage and computer room.

Fast forward to March 2015, when the Massachusetts US Attorney’s office told the jury in Tsarnaev a totally different story, painting a very clear picture of Dzhokhar living at the Norfolk Street apartment with his brother. Prosecutors even introduced as evidence a photo of the younger Tsarnaev in a bedroom at Norfolk Street, which a DOJ witness identified as Jahar's bedroom.

Last week, prosecutors spent nearly an entire day interviewing FBI agents who participated in the search of the Norfolk Street apartment. The jury heard that the house looked “like a construction site,” with tools, wires, and soldering equipment strewn around. When the defense, on cross-examination, asked a government witness about whether the FBI found fingerprints on these items, the prosecution objected. O’Toole sustained the objection.

Today in court, the defense brought an FBI technician to the stand as an expert witness. The line of questioning made clear that all of the incriminating evidence presented from the apartment bore Tamerlan’s fingerprints, but not Dzhokhar’s. On cross-examination, according to a reporter in the room, government prosecutors asked the FBI expert, “What if someone became an adult and moved out of their old house? You’d find fewer of their fingerprints?”

Confused yet?

To recap: In 2014 the DOJ told the court that Dzhokhar Tsarnaev was not a resident of the Norfolk Street apartment, and therefore couldn’t challenge the legality of any FBI searches there. In 2015 the DOJ tried to convince the jury that he was a resident of the apartment, and in great detail showed them a number of possibly incriminating items found inside it. But when confronted with the FBI’s own forensic evidence revealing that there are no fingerprints to show Dzhokhar ever touched any of the Norfolk Street items introduced into evidence, the DOJ returned to its original position: the young Tsarnaev had moved out, and so it makes sense that his prints weren't on this stuff.

But if he had moved out, and therefore his prints weren’t likely to be found on any of the incriminating evidence in the apartment, why was it introduced into court? Why did the government work so hard to convince the jury—just days before—that Tamerlan and Dzhokhar shared the apartment, when prosecutors made exactly the opposite argument a year ago?

The Feds can’t have it both ways. Either the apartment was Dzhokhar’s to begin with, and therefore his attorneys had standing to challenge the nature of its search, or he didn’t live there anymore, and the connection between the defendant and the items the government presented from the apartment is tenuous at best.

Not even the defense in this case disputes Jahar Tsarnaev’s guilt. Guilt is effectively a non-issue in this trial. The only real question for the jurors is whether Tsarnaev will face government executioners for his role in the horrific Boston Marathon bombings and their bizarre, bloody aftermath. The DOJ is pushing for the death penalty, but in order to convince the jury that the state should execute Jahar Tsarnaev, prosecutors must discredit an idea the defense has advanced since early in the proceedings—a narrative that says Jahar was just a kid who got caught up in his dangerous and menacing older brother’s whirlwind of violence and destruction. Jahar didn’t buy any of the weapons, this argument goes. His fingerprints aren’t on any of the bomb making materials. He didn’t plan the attack. His scary big brother did. And therefore, despite his involvement in these despicable crimes, the jury should spare him his life.

Mostly everyone in the Boston media has said the same thing about this case from day one: The evidence against Dzhokhar Tsarnaev is overwhelming. The only issue to be worked out in the trial is his punishment. And that’s precisely what is so disturbing about the federal government's narrative shape-shifting (of which this residence issue is just one example among many).

In a criminal investigation and trial, the prosecution’s job is to find the truth, and communicate it to the judge and jury. Their job is not to spin the facts whichever way suits the prosecution at any given moment—sometimes this way, and sometimes that.

Seen within the context of their insistence to seek the death penalty—against the wishes of the people of Boston—the back and forth game played by prosecutors with respect to Tsarnaev’s residency shocks the conscience. In order to convince the jury that Dzhokhar deserves to die, the DOJ appears to have decided to say whatever is convenient at any given time, playing fast and loose with the truth.

That’s troubling in any criminal prosecution. But when a government execution lies at the end of the story arc, this kind of conduct veers into something much more dangerous. And even if you hate Dzhokhar Tsarnaev, these prosecutorial tricks should worry you. That is, if you care about basic fairness in our courts and from our government.