Serial: The Failure of the Prosecution’s Cellphone Theory, In One Simple Chart

The prosecution’s case against Adnan can be summed up in three words: Leakin Park Pings. Again and again, the prosecution argued (and is still arguing) that Adnan’s guilt can be shown simply from the fact that his cellphone pinged a cell tower in Leakin Park at the same time that Jay, eventually, told police that Hae had been buried. Based on this claim, the prosecution invited the jury to stack speculative inference upon speculative inference: that the phone pinging L689B meant the phone is in L689B, that the phone being in L689B meant that the phone was at Hae’s burial site, that the phone being at Hae’s burial site meant Adnan has the phone. Because, the prosecution asks, what are the odds that the cellphone would ping the Leakin Park tower at the same time that its witness would say that the phone had been in Leakin Park, with someone who was burying Hae’s body?

Well, I have no idea what the odds of that are, and neither did the jury. Because the prosecution never presented any evidence whatsoever concerning the possible locations from which a phone call could ping the Leakin Park tower. The jury was only informed that the burial site was a location from which the cellphone might ping that tower — but there was no mention made whatsoever to the thousands of other locations from which a call could ping that tower, too.

But the tenuousness of the prosecution’s argument is not due merely to its claim about the precise location of the phone within L689B. It is also due to its claim that the cellphone was even in L689B’s territory at all. Because if the tower pings were capable of demonstrating the tower range in which the cellphone was located at the time of a call, as the prosecution claimed, how come the tower pings gave the wrong location for 16 of the 22 calls for which the prosecution’s evidence showed the location of the phone at the time of the call? And if the tower pings are only accurate 27% of the time, according to the prosecution’s own theory of the case, then how can we possibly assume that the tower pings just happened to be accurate for the Leakin Park tower pings, even when they are inaccurate in the overwhelming majority of all other calls?

Below is a table showing the tower pings for each call in comparison to the prosecution’s claims about the location of the phone at the time of each call. As you go through the table below, it may help to refer to this map of tower ranges:

Tower ranges show the territories for which the labeled tower is the closest tower/antenna.

The result? Out of the 30 calls that were made or received on the day of Hae’s murder, there were 22 calls for which the prosecution’s evidence identified the location of the cellphone at the time of the call. Of those 22 calls, only six pinged the tower that covers the range where, according to the prosecution, the cellphone was located. Of those six calls, one occurred while the cellphone was indisputably, according to the testimony of several witnesses, at Woodlawn High School (10:45 am), one occurred while the cellphone was indisputably, according to the testimony of several witnesses, at Cathy’s apartment (6:07 pm), and four occurred while the phone was allegedly in Leakin Park and when Hae’s car was being ditched (7:09, 7:16, 8:04, 8:05).

But isn’t that rather odd? Why is it that the location data for the cellphone is only accurate when we either have multiple non-Jay eyewitnesses who could testify as to the phone’s location at the time of the call, or when the phone was at a location where it absolutely must have been in order for the prosecution’s case against Adnan to hold up?

Could it possibly be that, for the 7:09, 7:16, 8:04, and 8:05 calls, the investigators refused to accept Jay’s story until he gave them an answer that fit their theory of the case? And that for every other call that was not directly incriminating, the investigation did not bother with making sure that Jay’s story actually fit the narrative they were pushing? Because based on the prosecution’s theory of the case, the only apparent explanation for the cellphone records is that the towers pings magically became more accurate from 7:09 to 8:05 p.m., even though they were overwhelmingly unreliable for the rest of that day. Well, either that, or else the prosecution selected a narrative that happened to fit the cellphone records in a way that made Adnan look guilty.

The prosecution’s entire case has gone into a fatal loop. Why are the cellphone records accurate? Because Jay says so. Why is Jay’s testimony accurate? Because the cellphone records say so. Why are the cellphone records accurate? Because… and so on, and so on. Except for one teeny little flaw in that premise: the cellphone records do not actually match Jay’s testimony, and Jay’s testimony does not actually match the cellphone records. So how can two things that do not match one another verify the accuracy of each other?

In other words: instead of asking, “What are the odds that the cellphone would ping Leakin Park if the phone was not there?”, the question we should really be asking is, “What are the odds that the incriminating portions of the prosecution’s theory of the case conveniently match the cellphone records, when everything else does not?”

-Susan

Edit: I should note that the maps I am using present the prosecution’s case in the strongest light possible — I am giving them every possible benefit of the doubt with the idealized territory of L689B.

But that is not how real life works. I am no graphic designer, so you’ll have to forgive the MS Paint rendition, but below is a representation of the signal range for L689 (in red), based on a signal range of two miles. Also included is a representation of the signal range for L653 (in blue). There was no evidence presented at Adnan’s trial concerning the possible range of any of the towers, so I adopted the two-mile figure based on the conservative estimate often used by law enforcement. The radial lines in the southern half of L689 show the direction of the B antenna (“L689B”). Note that the majority of L689B’s signal range, based on the two-mile assumption (which would appear to be consistent with the closest-territory range of L689A and L689C), is not in Leakin Park at all, but in the neighboring territory.

And here is a map showing an actual coverage map (h/t /u/gentrfam). Note that this map does not even show the extent of the overlap of these ranges, although it is a good illustration of the random nature (and noncontiguous blobs of coverage) that real life cell towers provide: