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County District Court No. 14CR2888 Honorable Tamara S.
J. Weiser, Attorney General, Jillian J. Price, Senior
Assistant Attorney General, Denver, Colorado, for
Lauretta A. Martin Neff, Alternate Defense Counsel, Grand
Junction, Colorado, for Defendant-Appellant.
Defendant Charles Jenson Shanks appeals from his conviction
on two counts of kidnapping, two counts of burglary, and one
count each of robbery, felony menacing, assault, and false
imprisonment. He contends that the district court erred by
(1) admitting expert witness testimony about historical cell
site analysis without first conducting an evidentiary
hearing; (2) admitting an impermissibly suggestive
out-of-court identification and an in-court identification
based thereon; (3) excluding his alternate suspect defense;
and (4) allowing the use of his nickname, "Capone,"
at trial. He also contends that the cumulative effect of
these errors warrants reversal. We affirm.
Addressing an issue of first impression in Colorado, we
conclude that expert testimony explaining how historic cell
site data is used to provide a general geographic location of
a cell phone at a given time may be admitted without first
holding an evidentiary hearing on the reliability of the
Shanks and his codefendant, William Cody, were charged with
numerous offenses arising from the home invasion and assault
of the victim.
The victim and Cody worked together and occasionally
socialized outside of work. The victim supplied Cody with
marijuana and the two men sometimes smoked marijuana
together. On the night of the charged offenses, Cody called
the victim to purchase some marijuana and arranged for his
"sister," codefendant Arianna Eastman, to pick it
up for him.
The victim met Eastman outside his house for the transaction.
When he turned to go back inside, a masked man, whom the
victim later identified as Cody, and another unmasked man
followed him and forced their way inside. The two assailants
searched the apartment and beat up the victim before leaving
with the victim's equipment for growing marijuana.
A couple of days after this incident, the victim identified
Shanks as the second assailant from a photo array. The victim
identified Shanks again during trial.
A jury ultimately convicted Shanks as charged. The court
sentenced him to twenty-eight years in the custody of the
Department of Corrections.
Historical Cell Site Analysis
Shanks contends that the district court erred by admitting
expert witness testimony analyzing historical cell site data
without first holding a hearing to determine the reliability
of the science behind such analysis. We disagree.
Standard of Review
We review the district court's admission of expert
testimony for an abuse of discretion and will reverse only
when the decision is manifestly erroneous. See People v.
Rector, 248 P.3d 1196, 1200 (Colo. 2011). "This
deference reflects the superior opportunity of the trial
judge to assess the competence of the expert and to assess
whether the expert's opinion will be helpful to the
A trial court determines the admissibility of expert
testimony under CRE 702, which provides as follows:
If scientific, technical, or other specialized knowledge
will assist the trier of fact to understand the evidence or
to determine a fact in issue, a witness qualified as an
expert by knowledge, skill, experience, training, or
education, may testify thereto in the form of an opinion or
inquiry focuses on "the reliability and relevance of the
proffered evidence and requires a determination as to (1) the
reliability of the scientific principles, (2) the
qualifications of the witness, and (3) the usefulness of the
testimony to the jury." People v. Shreck, 22
P.3d 68, 70 (Colo. 2001); accord People v. Campbell,
2018 COA 5, ¶40, 425 P.3d 1163. The court must also evaluate
the evidence under CRE 403, ensuring that the probative value
is not substantially outweighed by the danger of unfair
prejudice. See Rector, 248 P.3d at 1200;
Shreck, 22 P.3d at 70.
The court's inquiry "should be broad in nature and
consider the totality of the circumstances of each specific
case." Shreck, 22 P.3d at 77; accord
Rector, 248 P.3d at 1200. Although the factors set forth
in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509
U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993), provide
helpful guidance, a court need not consider any specific set
of factors when determining the reliability of the proffered
evidence. Shreck, 22 P.3d at 78.
Concerns about conflicting opinions or whether a qualified
expert accurately applied a reliable methodology go to the
weight of the evidence, not its admissibility. See
Campbell, ¶42. "Such concerns `are adequately
addressed by vigorous cross-examination, presentation of
contrary evidence, and careful instruction on the burden of
proof.'" Id. (quoting Estate of Ford v.
Eicher, 250 P.3d 262, 269 (Colo. 2011)).
If a party requests that evidence be subjected to a
Shreck analysis, the trial court may, in its
discretion, hold an evidentiary hearing. Id. at ¶41.
"This discretion comports with the trial court's
need to `avoid unnecessary reliability proceedings in
ordinary cases where the reliability of an expert's
methods is properly taken for granted, and to require
appropriate proceedings in the less usual or more complex
cases where cause for questioning the expert's
reliability arises.'" Rector, 248 P.3d at
1201 (quoting Kumho Tire Co. v. Carmichael, 526 U.S.
137, 152, 119 S.Ct. 1167, 143 L.Ed.2d 238 (1999)). A hearing
is not required if the court "has before it sufficient
information to make specific findings under CRE 403 and CRE
702 about the reliability of the scientific principles
involved, the expert's qualification to testify to such
matters, the helpfulness to the jury, and potential
Shanks's defense was that he was not the second assailant
and that he was at a family gathering on the other side of
town (about eighteen miles southeast of the victim's
house) at the time of the offense. The prosecution intended
to disprove this defense by introducing evidence from
Shanks's phone records and cell tower usage data to show
that he was in the general area of the victim's home at
the time of the offense. To do so, the prosecution disclosed
investigator Kathleen Battan as an expert in "Forensic
Analysis of Cellular Phone Records and Cell Tower Function
and Data." Defense counsel objected and requested a
In its order denying the hearing request, the district court
noted that whether a Shreck hearing is required to
determine the admissibility of historical cell site analysis
is a novel issue in Colorado. It then reviewed federal case
law analyzing the issue under Fed.R.Evid. 702, which is
similar to Colorado's rule for our purposes, before
federal courts have generally required a pretrial hearing
to determine the admissibility of expert testimony
purporting to pinpoint the location of a defendant using
cell phone site data, whereas a pretrial hearing has
generally not been required to determine the admissibility
of testimony merely purporting to place a defendant within
the service radius of a specific tower at a certain time.
Concluding that the prosecution's proffered evidence fell
into the latter category — identifying Shanks's
general location when the crime was committed — the
district court denied the request for a hearing.
Shanks renewed his objection and request for hearing multiple
times, arguing that Ms. Battan based her opinion on a theory
called "granulization" and the "scientifically
unsupported assumption that a cell phone connects to the
closest cell tower." Shanks also challenged Ms.
Battan's use of pie shaped sectors rather than ovals to
demonstrate the cell tower service area. Again, the district
court denied the request for hearing.
At trial, over Shanks's objection, the district court
accepted Ms. Battan as an expert and allowed her to testify
"about forensic analysis of cellphone records ... and
also in a limited fashion about ... cell tower function and
data." The court acknowledged that Ms. Battan did not
have a background in science or engineering but concluded she
did not need to "know how to design, operate or
manufacture cell towers" to testify about the cell tower
data she collects and "what that data tells her about
cell tower function."
Ms. Battan testified to the following:
• Typically, a cell tower has three sectors, each
covering approximately 120 degrees of a 360-degree circle
around the tower. The orientation of the sector (the
precise direction the sector points) is called the azimuth.
• Law enforcement has access to a database that
includes the precise physical location of all cell towers
and the azimuth of each sector of each tower.
• Shanks's cell phone carrier produced records
that included data about when each call was made or
received, how long the call lasted, and what specific
sector of what cell tower was used by the cell phone to
make or receive the call.
• She mapped the physical location of the cell
towers used by Shanks's carrier using Google Earth;
identified the towers closest to Shanks's residence,
Cody's residence, and the victim's residence; and
noted that there were approximately 100 towers in between.
• Using an FBI computer program, she plotted the
cell tower and sector used for each relevant call reflected
in Shanks's phone records. The sectors ...