Destination Unknown: More on the Cell Tower Pings From Episode 8 of Undisclosed

On yesterday's episode of the Undisclosed Podcast, I noted how Cristina Gutierrez could and should have moved for a Frye hearing regarding the admissibility of the cell tower pings at Adnan's trial. I further concluded that the result of such a hearing would have been (1) the court certainly deeming the incoming pings inadmissible based upon AT&T's own disclaimer that such pings are not reliable for determining location; and (2) the court quite possibly deeming all pings inadmissible based upon the irregularities in how the testing was done (e.g., the prosecutor selectively writing down things called out by the cell phone expert). In this post, I wanted to flesh out the analysis a bit more.

Here's the Frye case. As noted, the defendant in that case sought to admit the results of his lie detector test into evidence. In rejecting his proffer, the court concluded as follows:

Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.

We think the systolic blood pressure deception test has not yet gained such standing and scientific recognition among physiological and psychological authorities as would justify the courts in admitting expert testimony deduced from the discovery, development, and experiments thus far made.

In the Daubert case (1993) the Supreme Court rejected this Frye/"general acceptance" test for federal courts and created the notion of judge as gatekeeper, independently assessing the reliability of expert. At least 30 states subsequently followed suit, but not Maryland.

The Court of Appeals of Maryland extensively discussed the Frye test in Reed v. State, noting that

The Frye test has been subjected to some criticism, primarily on the grounds that it is too conservative and unduly prevents or delays the admission of relevant scientific evidence....There are, however, compelling reasons which justify the Frye principle.

Fairness to a litigant would seem to require that before the results of a Scientific process can be used against him, he is entitled to a Scientific judgment on the reliability of that process....

Under the Frye test,...[a]s long as the scientific community remains significantly divided, results of controversial techniques will not be admitted, and all defendants will face the same burdens. If, on the other hand, a novel scientific process does achieve general acceptance in the scientific community, there will likely be as little dispute over its reliability as there is now concerning other areas of forensic science which have been deemed admissible under the Frye standard, such as blood tests, ballistics tests, etc.

As you can see, the Frye test is very conservative/stodgy. It doesn't allow for emerging expert evidence to be admitted until it has general acceptance; even a divide in opinion will lead to exclusion. And the reason for this stodginess is "[f]airness to a litigant." Frye jurisdictions don't want defendants to be convicted on the basis of expert evidence that is of questionable reliability.

Because Frye was extensively discussed in Reed v. State, Maryland courts refer to Frye hearings as Frye/Reed hearings. As I mentioned on the podcast, these hearings are pretty straightforward. As such, there aren't usually ground for a defendant to appeal. That said, sometimes errors are made, as in Clemons v. State, 896 A.2d 1059 (Md. 2006). In Clemons, evidence from a comparative bullet lead analysis (CBLA) was admitted after a Frye/Reed hearing. On appeal, the Court of Appeals of Maryland found that this was erroneous, concluding that

The only consensus that can be derived from all of [the evidence on the issue] is that more studies must be conducted regarding the validity and reliability of CBLA. Although scientific unanimity is not required to satisfy the Frye-Reed test's requirement of general acceptance,...it is clear that a genuine controversy exists within the relevant scientific community about the reliability and validity of CBLA. Based on the criticism of the processes and assumptions underlying CBLA, we determine that the trial court erred in admitting expert testimony based on CBLA because of the lack of general acceptance of the process in the scientific community.

Now, let's return to Adnan's case. AT&T's disclaimer pretty clearly means that the incoming pings would have been deemed unreliable and inadmissible under Frye. Moreover, given that Adnan's case was the first one involving cell tower pings in Maryland, and given the odd way in which the testing was done, I think there's a good chance that the pings would have been deemed inadmissible altogether.

-CM