February 8, 2019
Defendants Motion in Limine to Exclude Expert Testimony,
H. Puit, Esquire, Matthew B. Frawley, Esquire, Jenna R.
Milecki, Esquire (argued), Department of Justice, Wilmington,
Delaware, Attorneys for the State.
J. Maurer, Jr., Esquire, Elise K. Wolpert, Esquire (argued),
Wilmington, Delaware, Attorneys for Defendant.
a murder case. The State alleges that Defendant, Steven
Pierce, shot and killed his girlfriend, Heather Stamper, on
July 9, 2016 in her Delaware City home. The State proposes to
introduce evidence tracking Defendants movements for the
23-hour period before and after the approximate time of
death. Defendant seeks to exclude the Google Wi-Fi Location
Data used to "geolocate"
Defendants cell phone on the grounds that the proposed
evidence is not sufficiently reliable under the
Daubert standard and would mislead and confuse the
jury. The State argues that the technology at issue is
reliable and would be helpful to the finder of fact. The
reliability of Googles Wi-Fi Location Data is an issue of
first impression in Delaware.
was indicted by the Grand Jury on December 5, 2016, and
charged with Murder in the First Degree and Possession of a
Deadly Weapon During the Commission of a Felony for the
intentional murder of Heather Stamper. The case was specially
assigned to this Trial Judge. The trial was initially
scheduled for January 2018 but was rescheduled when Defendant
retained new counsel who was unavailable for that trial
date. A new trial date was set for August
5, 2018, Defendant sought permission of the Court to file two
motions after the deadline imposed by the Court for pre-trial
motions: a motion to suppress certain evidence and a
Daubert motion. The Court did not address the motion
to suppress because the parties reached an agreement that the
State would not use the challenged evidence in the States
case-in-chief. Regarding the Daubert motion, the
Court conducted an office conference on June 28, 2018, at
which time it became clear that resolution of the novel issue
involved would require that the trial date be rescheduled
again. Accordingly, the Court conducted a hearing on July 6,
2018 to address Defendant personally regarding his right to a
Court found that Defendants waiver of his speedy trial
rights was knowing, intelligent, and voluntary. By Order
dated July 6, 2018, the Court granted Defendants Motion to
File a Daubert Motion Out-Of-Time, over the States
objection. A new Trial Scheduling Order was issued, setting
the date for trial as April 2, 2019, and setting forth
deadlines for discovery and briefing in connection with
Defendants Daubert motion.
Court conducted a Daubert hearing on November 27,
2018. In support of the reliability of the States proposed
evidence, the State presented the testimony of Andrew Rist,
an engineer, and Anthony Vega, a law enforcement officer. The
States two witnesses were subject to cross-examination by
Defendant. The parties submitted post-hearing briefs.
TECHNOLOGY AT ISSUE 
to the United States Supreme Court, in 2018, there were 396
million cell phone service accounts in the United
States. The High Court emphasized that there
are more cell phone accounts in the United States than there
are people. The most popular mobile devices have
one of two operating systems that control the functioning of
the phone. For Apple phones, it is iPhone Operating System
("iOS") and for Google phones and many other phone
manufacturers, it is Android.
phone was a MetroPCS phone with the Android operating system.
While there are similarities between Apples iOS and Googles
Android as it relates to capturing user data, the technology
at issue in this case involves location data derived from
communications between an Android mobile device and Google.
(The data is referenced herein as "Google Wi-Fi Location
Data"). Specifically, the subject of the
Daubert motion in
this case was the Wi-Fi-sourced geolocation information
associated with a unique Google account transmitted from the
Android operating system on Defendants mobile device and
stored by Google.
phone using the Android operating system serves as a data
collection device as it continuously collects and sends
information to Google as "events" approximately
every 10-20 minutes. Meanwhile, other programs on the phone
are running, either actively by the cell phone user, or idly
in the background. These applications often rely upon Google
Wi-Fi Location Data to customize information sent by Google
to the user. With each event, there are various
categories of information sent back to Google, including the
devices location history which is comprised of GPS, cellular
data, and recognized Wi-Fi signals. Google collects and
retains fairly detailed location information, including
time-stamped barometer readings to determine the devices
altitude, such as the floor within a building, and Wi-Fi
scans recorded with a time stamp for each location, noting
latitude, longitude, and estimated accuracy.
Wi-Fi Location Data is not considered first-generation
technology for geolocation. Global Positioning System
("GPS"), a utility owned by the United States
government, uses satellites for positioning, navigation, and
timing ("PNT") services. GPS receiver equipment is
found in many mobile devices, including cell phones and
vehicle navigation systems. Mobile devices exchange signals
with GPS satellites and use the transmitted information to
calculate the users position. Under open skies,
"GPS-enabled smartphones are typically accurate to
within a 4.9 meter radius." The accuracy of GPS can
be compromised by many factors, including satellite signal
blockage due ...