Marathon #7: Let’s Do the Math

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Let’s Do the Math

What is an alibi defense, and does Dzhokhar Tsarnaev have one in regards to the charges for which he was convicted? Attorney Tom Frizzell returns to break down trial transcripts and help Heather determine whether Dzhokhar was involved with gathering the bomb-making materials that were used in the Boston Marathon bombing. Despite what was reported in the media, the information on the record is far more exculpatory than one might expect.

Episode Extras

Update: It’s come to my attention that my dad and I misspoke when we said Tamerlan had receipts for the pressure cookers and BBs on his person. These receipts were obtained by the FBI through the Macy’s and Walmart stores. However, there was a note found among Tamerlan’s possessions with the addresses of three New Hampshire area Walmarts, one being the Hudson location mentioned in the transcript. See below for exhibit photos.

Court Transcripts
Government witness FBI Agent Christian Fierabend
Defense witness Gerald R. Grant

Surveillance photo of Tamerlan Tsarnaev buying backpacks alone
Photo of Target receipt for backpacks found in Tamerlan’s possession
Photo of handwritten note with Walmart addresses found in Tamerlan’s possession

Relevant blog post
Our trip from the Square One Mall in Saugus to UMass Dartmouth

And, just to reiterate the end note in the podcast:

I would like to give special thanks to a tip from a reader who mentioned that the Target backpack receipts from Tamerlan did not account for both backpacks that exploded at the Marathon. I know there’s a lot of speculation out there about the backpacks not matching, but with this tip I was able to find it and confirm it in the court records. So I stand corrected on that point: the backpack at the second blast site attributed to Dzhokhar did not come from Tamerlan’s purchases. But it didn’t come from Dzhokhar’s, either. Which leaves the question: where did it come from?

The large number of discrepancies and unaccounted for purchases in the bomb materials — as well as the fact that there were actually three pressure cooker bombs in backpacks — is going to be the subject of upcoming written posts on my blog. In these, I will try to answer a question I’ve had for quite some time: if Dzhokhar was not involved with the bombing conspiracy with Tamerlan, then who was? Is there at least one unnamed accomplice out there who never saw the inside of a courtroom for his or her involvement? Did Dzhokhar, in essence, suffer in the place of another co-conspirator or conspirators, while they walked free?

I think the answer is yes.

The rest of this summer will be dedicated to my blog posts on this subject. It’s something I’ve been pursuing since 2015, but it wasn’t until recently I had enough pieces to put together to form any kind of picture. Please stay tuned for those installments by going to and hitting the Follow button, or by subscribing for updates via Twitter @USvTsarnaev or at The podcast will be on a bit of a hiatus, but I am hoping to do at least one more Q&A with my dad soon, so if you have any burning questions about the case, please contact me by Twitter, Facebook, blog comment or by sending me an email at

Thank you and stay tuned!

16 thoughts on “Marathon #7: Let’s Do the Math”

  1. Thank you Heather for another wonderful podcast. This one was my favorite so far. I really love hearing your dad’s legal perspectives on the case.
    One of the things that stood out to me while listening to the podcast was the mention that they found receipts for the pressure cookers and the BBs in Tamerlan’s wallet. It was my understanding that they didn’t actually find receipts on his person but that they were able to get evidence from the Macy’s and Walmart stores that those purchases were made during approximately the same timeframe as the gps memory evidence put Tamerlan (or so they suggested) in the area. just wanted to mention that just in case you were able to find evidence that was presented to the contrary.

    Thanks again.

    1. Thanks for another great Podcast Heather. I’d like to know too. I always read that the receipt was found in his wallet (and I thought it was a bit weird).

      This is a picture of what was in Tamerlan’s wallet I believe.

      There is a receipt from Target for 2 backpacks but I can’t see the receipt for the pressure cookers.

      Which leads me to another question. The backpack Jahar was seen with at the marathon was also found in his room (or was it at Tamerlan apartment?) after his arrest. So it means there were 2 of the same backpack (or the backpack Jahar was carrying never exploded and made it’s way back to his room). So according to the receipt 2 backpacks were bought. And if we decide that Jahar’s backpack exploded at the marathon, it means that

      A) Tamerlan bought two of the same backpack and somehow, only gave one to Jahar and used a different one for himself

      B) Tamerlan bought a backpack similar to the one Jahar already had and bought a different for himself

      It is nothing incriminating or exonerating but it is a bit weird, especially since every little bit of evidence in this case has something weird to it. Why buy 2 backpacks the day before and only use one? Or why buy two different backpacks, but one exactly identical to one Jahar already had? It obviously is not impossible, but it does seem weird to me.

      1. I just realised the prices of the backpacks are different so he bought two back packs which seems to mean he bought an exact replica of a backpack Jahar (or himself already owned)

      2. I’m not aware of any other backpack that was recovered from Dzhokhar’s dorm room or the Norfolk St. residence. Do you know where on the record it says that? To my knowledge, Dzhokhar’s school backpack was recovered from a landfill after his friends took it from his dorm and disposed of it. I don’t think it was similar in color to the one at the Marathon. In the photos I’ve seen it was plaid, I think. I’ve never seen anything that identifies the backpack he was carrying at the Marathon as anything other than the one that exploded. If there’s evidence that speaks to that, I would love to see it, because right now that second backpack (as well as one of the two pressure cookers that exploded that day) is appearing out of thin air and that’s really disturbing to me.

        The important distinction here is that the two backpacks Tamerlan bought at Target the day before are NOT the two backpacks the brothers were carrying at the Marathon; only Tamerlan’s was. At the moment we have no indication where the second backpack came from. The other backpack purchased by Tamerlan was found at the Watertown shootout scene with the third pressure cooker bomb.

        I absolutely agree with you, though: why buy an excess backpack the day before (and have an excess bomb, for that matter!) if you’re only intending to detonate two?

        That’s why I think it’s not only possible but likely that Tamerlan had other accomplices. The available evidence makes WAY more sense if there were three perpetrators and therefore three pressure cooker bombs in backpacks for them to deliver at the Marathon. Add to that Dzhokhar’s complete lack of involvement in the preparation beforehand (or any sign he was “radicalized” or intent to commit political violence) and it makes me think that whoever Tamerlan’s other accomplices were pulled out last minute. The whole thing reeks to me of improvisation on Tamerlan’s part, with Dzhokhar’s involvement completely contingent on the fact that he just happened to be around that day, since Patriot’s Day is a school holiday and he wouldn’t have had to be on campus. The Marathon is such a well-known and well-attended public event that it isn’t a stretch to think that “Hey, let’s go to the Marathon and see what’s going on” would have been enough to get him there.

        But I’ll be expanding on that theory in the coming weeks.

    2. I have some exhibit photos, and I was able to get a larger photo of the Target receipt in case anyone would like to see it:

      However, my exhibit collection isn’t complete, so I don’t have every single exhibit that the transcripts reference, unfortunately. I’m not not seeing receipts for the pressure cookers or the BBs, but I am seeing a handwritten note with the address of at least one of the Walmarts among Tamerlan’s possessions:

      I’m looking at the transcript again, and you’re right, it looks like the FBI obtained the Walmart and Macy’s receipts from the stores themselves, rather than from Tamerlan. However, the GPS data is definitely coming from the GPS that was in Tamerlan’s possession. I’m going to look at this in more detail and break down what purchases are and aren’t accounted for in my upcoming blog posts, so I might be able to dig up some better photos and explanations then.

      Thanks for pointing that out!

  2. Now I’m off to actually listen to the end of teh podcast, you might have talked about it already 😀

  3. All I can find now is this picture

    I remember seeing better pictures and more context but I cannot find anything right now. I will have to do some research. But, yes, during the search at what I think is Tamerlan’s apartment, after Jahar’s arrest, you can see something that looks strangely like the backpack Jahar’s had at the marathon.

    Now, as I say, that picture is a bit confusing, I remember seeing a better one.

    1. Hmm. I’ll have to see if I can find anything like this in my own exhibit photos. I’m wary of anything that comes from the internet and not the official record. I’ve seen some obviously photoshopped content in the past (including a shot of Dzhokhar on a street that I recognized as not Boylston Street, since I used to work in that part of Boston and was on Bolyston almost daily). Since this has already been doctored to be a comparison shot, it’s possible it was faked. Is there any identifying exhibit number attached to the lefthand photo? That would help a lot.

    1. Although now I look, I am really not sure it is the same.. I am confused (I need to change my name to confusedintheSand, I swear)

      1. Yeah, while the outside photos match the property I’ve seen, the article itself gets key details wrong (Dzhokhar and Tamerlan never robbed a 7/11, for instance). And I’m not sure I believe the NY Daily News (which doesn’t have a great reputation as a publication) was able to get into the apartment the day after Dzhokhar was captured. I would think the Norfolk St. apartment might still be an active crime scene at that point and would have been crawling with law enforcement. Also, it was definitively established at trial that Tamerlan’s wife and daughter were living in the apartment at the time, so that doesn’t match either. On top of all that, the lefthand photo in the comparison picture doesn’t look like it comes from any of the photos in this article. Edit: Okay, I actually see the photo used in comparison now, but up close it looks like it could be a tent of some kind, instead of a backpack? Still, like I said, I’m not sure I buy any of these photos are from inside the apartment, given the unreliability of the source.

        This is why I try to stick to evidence on the official court record unless I can thoroughly vet the source myself. There’s a lot of speculation out there and it’s super easy to get lost in the weeds.

  4. No you are right. But isn’t there a list of every single thing found in the apartment in the evidence?

    Also, the comparison picture is the 5th picture in the article no?

    I also spotted the mistakes, but I assumed there were still a lot of that BS circulating at the time.

    I have no idea if this is true or false, but I agree it would be weird they had access to the apartment, unless the search was done and an officer let them in. But actually looking at the picture it seems like it might actually be on the landing so is there any possibility they never made it into the apartment (hence the picture thats seems to be taken from a whole in the door) but the FBI left stuff they didn’t take or need on the landing in front of the flat and a neighbour let the photographer in? So I guess that is why it would be interesting if there was an inventory.

    1. Haha, yes, sorry, I saw the original photo once I looked again, and it looks like it could be a camping tent perhaps? No, by April 20th the story was pretty cemented to what ended up being at trial in regards to the night of April 18th and the carjacking of Dun Meng; I didn’t hear anything about a supposed 7/11 robbery at the time. Also, a decent publication would have checked to make sure that wasn’t a mistake before they printed it. All your other points are valid, though. I noticed a lot of the photos looked like they were on landings too, but I’ve never been inside the building so I can’t say for sure what it looks like. I’ve seen some of the exhibit photos from inside the apartment, and they don’t look much like this, but there are probably more on record than what I’ve seen. “Ramshackle” seems like an unfair descriptor regardless, considering how law enforcement undoubtedly turned the place inside out.

      I’d also like to give the defense the benefit of the doubt here. If there was a backpack matching the one Dzhokhar had at the Marathon recovered at his residence, they would probably have used that as part of their case. Surveillance footage pretty conclusively shows he doesn’t have it once he flees the scene, though, so that would beg the question of how a backpack magically teleported from the site of an explosion back to his apartment without him.

      1. I have no idea (sorry lol)

        I must say that the “journalist” lost me at “…pair shared a squalid existence “.

      2. Also inaccurate, because Dzhokhar was more than an hour away at UMass Dartmouth far more than he was back in Cambridge (which is far from a squalid place to live!).

        I do recall early and unfounded attempts to paint the brothers as extremely insular and isolated (I remember being surprised to learn they had sisters and Tamerlan a wife and child), which surely only fueled the inaccurate narrative that they were conspiring completely on their own. This article was probably part of that. That’s been disproven with the trial record, although sadly the misconception that they had to be sole co-conspirators lives on, which is what I’m planning to challenge going forward.

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