Jefferson County District Court No. 14CR2888 Honorable Tamara
S. Russell, Judge
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
1 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.
2 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
3 Shanks and his codefendant, William Cody, were charged with
numerous offenses arising from the home invasion and assault
of the victim.
4 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.
5 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
6 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.
7 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
8 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
9 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
10 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 otherwise.
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. 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.
11 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 (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.
12 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.
13 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 (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 prejudice."
14 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 Shreck hearing.
15 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 ruling that
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.
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.
16 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.
17 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."
18 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 associated with each
call were reflected on the exhibits as 120-degree wedges with
green lines as the general boundaries of the sector and a
shaded green area between the lines. The lines did
not depict distance from the cell tower.
• She cannot state how far away a cell phone is
from a given cell tower during a call or exactly where a cell
phone is when it uses a particular tower.
• Many cell tower coverages overlap and a call typically
will use the cell tower with the clearest and strongest
signal even if that tower is not the closest. Which tower a
phone uses is determined ...